SSC3S900

SSC3S900 SANKEN | Alldatasheet

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Technical content

Datasheet sections

• 8.1 Resonant Circuit Operation -------------------------------- -------------------------------- -----
• 8.2 Startup Operation -------------------------------- -------------------------------- -----------------
• 8.3 Undervoltage Lockout (UVLO) -------------------------------- --------------------------------
• 8.4 Bias Assist Function-------------------------------- -------------------------------- ---------------
• 8.6 Minimum and Maximum Switching Frequency Setting -------------------------------- ---
• 8.8 Constant Voltage Control Operation -------------------------------- --------------------------
• 8.9 Standby Function -------------------------------- -------------------------------- ------------------
• 8.9.1 Standby Mode Changed by External Signal -------------------------------- -----------
• 8.9.2 Burst Oscillation Operation -------------------------------- -------------------------------
• 8.10 Automatic Dead Time Adjustment Function -------------------------------- ----------------
• 8.11 Brown-In and Brown-Out Function -------------------------------- ---------------------------
• 8.12 Capacitive Mode Detection Function -------------------------------- --------------------------
• 8.13 Input Electrolytic Capacitor Discharge Function -------------------------------- -----------
• 8.14 Reset Detection Function -------------------------------- -------------------------------- --------
• 8.15 Overvoltage Protection (OVP) -------------------------------- -------------------------------- --
• 8.16 Overcurrent Protection (OCP) -------------------------------- -------------------------------- -
• 8.17 Overload Protection (OLP) with Input Voltage Compensation --------------------------
• 8.17.1 Overload Protection (OLP) -------------------------------- --------------------------------
• 8.17.2 OLP Input Voltage Compensation Function -------------------------------- -----------
• 8.18 Thermal Shutdown (TSD) -------------------------------- -------------------------------- -------
• 9.1 External Components -------------------------------- -------------------------------- ------------
• 9.1.1 Input and output electrolytic capacitors -------------------------------- ----------------
• 9.1.2 Resonant transformer -------------------------------- -------------------------------- ------
• 9.1.3 Current detection resistor, ROCP -------------------------------- --------------------------
• 9.1.4 Current resonant capacitor, Ci -------------------------------- ---------------------------
• 9.1.5 Gate Pin Peripheral Circuit -------------------------------- -------------------------------
• 9.2 PCB Trace Layout and Component Placement -------------------------------- -------------

Features

• Standby Mode Change Function ▫ Output Power at Light Load: P O = 100 mW (PIN = 0.27 W, as a reference with discharge resistor of 1MΩ for across the line capacitor) ▫ Burst operation in standby mode ▫ Soft-on/Soft-off function: reduces audible noise
• Realizing power supply with universal mains input voltage
• Floating Drive Circuit: drives a high -side power MOSFET directly
• Soft-start Function
• Capacitive Mode Detection Function
• Reset Detection Function
• Automatic Dead Time Adjustment Function
• Brown-In and Brown-Out Function
• Built-in Startup Circuit
• Input Electrolytic Capacitor Discharge Function
• Protections ▫ High-side Driver UVLO ▫ Overcurrent Protection (OCP): Peak drain current detection, 2-step detection ▫ Overload Protection (OLP) with Input Voltage Compensation ▫ Overvoltage Protection (OVP) ▫ Thermal Shutdown (TSD) Typical Application Package SOP18 Not to scale Lineup Product Protection Operation UVLO / OCP OLP / OVP / TSD SSC3S901 Auto Restart Auto Restart SSC3S902 Auto Restart Latch Shutdown Application Switching power supplies for electronic devices such as:
• Digital appliances: LCD television and so forth
• Office automation (OA) equipment : server, multi - function printer, and so forth
• Industrial apparatus
• Communication facilities 余白上 35mm VAC VSPL VSEN VCC FB ST NC VGH VS VB NC REG CSS CL PL VGL GND RC SB Standby VOUT2 GND VOUT1 PC1 PC2 PC1 PC2 SSC3S900

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 3 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 1. Absolute Maximum Ratings

• The polarity value for current specifies a sink as "+," and a source as "−," referencing the IC.
• Unless otherwise specified, TA is 25°C Characteristic Symbol Pins Rating Unit VSEN Pin Sink Current ISEN 1 − 10 1.0 mA Control Part Input Voltage VCC 2 − 10 −0.3 to 35 V FB Pin Voltage VFB 3 − 10 −0.3 to 6 V VSPL Pin Sink Current ISPL 4 − 10 1.0 mA CSS Pin Voltage VCSS 5 − 10 −0.3 to 6 V CL Pin Voltage VCL 6 − 10 −0.3 to 6 V RC Pin Voltage VRC 7 − 10 −6 to 6 V PL Pin Voltage VPL 8 − 10 −0.3 to 6 V SB Pin Sink Current ISB 9 − 10 100 μA VGL pin Voltage VGL 11 − 10 −0.3 to VREG+0.3 V REG pin Source Current IREG 12 − 10 −10.0 mA Voltage Between VB Pin and VS Pin VB−VS 14 − 15 −0.3 to 19.2 V VS Pin Voltage VS 15 − 10 − 1 to 600 V VGH Pin Voltage VGH 16 − 10 VS−0.3 to VB+0.3 V ST Pin Voltage VST 18 − 10 −0.3 to 600 V Operating Ambient Temperature TOP − −40 to 85 °C Storage Temperature Tstg − −40 to 125 °C Junction Temperature TJ − 150 °C * S urge voltage withstand (Human body model) of No.14, 15, 16 and 18 is guaranteed 1000V. Other pins are guaranteed 2000V.

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 4 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 2. Electrical Characteristics

• The polarity value for current specifies a sink as "+," and a source as "−," referencing the IC.
• Unless otherwise specified, TA is 25 °C, VCC is 19 V Characteristic Symbol Conditions Pins Min. Typ. Max. Unit Notes Start Circuit and Circuit Current Operation Start Voltage VCC(ON) 2 − 10 12.9 14.0 15.1 V Operation Stop Voltage VCC(OFF) 2 − 10 9.0 9.8 10.6 V Startup Current Biasing Threshold Voltage* VCC(BIAS) 2 − 10 10.1 11.0 11.9 V Circuit Current in Operation ICC(ON) 2 − 10 − − 10.0 mA Circuit Current in Non-Operation ICC(OFF) VCC = 9V 2 − 10 － 1.0 2.0 mA Startup Current ICC(ST) 2 − 10 3.0 6.0 9.0 mA VCC Pin Protection Circuit Release Threshold Voltage (1) VCC(P.OFF) 2 − 10 9.0 9.8 10.6 V SSC3S901 VCC Pin Latch Protection Circuit Release Threshold Voltage (2) VCC(L.OFF) 2 − 10 6.5 7.8 9.0 V SSC3S902 Circuit Current in Protection ICC(P) VCC = 11V 2 − 10 − 1.0 2.0 mA Oscillator Minimum Frequency f(MIN) 11 – 10 16 − 15 28.5 32.0 35.5 kHz Maximum Frequency f(MAX) 11 – 10 16 − 15 230 300 380 kHz Minimum Dead-Time td(MIN) 11 – 10 16 − 15 0.20 0.35 0.50 µs Maximum Dead-Time td(MAX) 11 – 10 16 − 15 1.20 1.65 2.10 µs Externally Adjusted Minimum Frequency f(MIN)ADJ RCSS = 30kΩ 11 – 10 16 − 15 70.0 74.0 78.0 kHz Feedback Control FB Pin Oscillation Start Threshold Voltage VFB(ON) 3 – 10 0.15 0.30 0.45 V FB Pin Oscillation Stop Threshold Voltage VFB(OFF) 3 – 10 0.05 0.20 0.35 V FB Pin Maximum Source Current IFB(MAX) VFB = 0V 3 – 10 − 300 − 195 − 100 µA Soft-start CSS Pin Charging Current ICSS(C) 5 – 10 − 120 − 105 − 90 µA CSS Pin Reset Current ICSS(R) VCC = 9V 5 – 10 1.2 1.8 2.4 mA Maximum Frequency in Soft-start f(MAX)SS 11 – 10 16 − 15 400 500 600 kHz Standby SB Pin Standby Threshold Voltage VSB(STB) 9 – 10 4.5 5.0 5.5 V SB Pin Oscillation Start Threshold Voltage VSB(ON) 9 – 10 0.5 0.6 0.7 V (1) VCC(P.OFF) = VCC(OFF) < VCC(BIAS) always. (2) VCC(L.OFF) < VCC(OFF) < VCC(BIAS) always.

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 5 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 Characteristic Symbol Conditions Pins Min. Typ. Max. Unit Notes SB Pin Oscillation Stop Threshold Voltage VSB(OFF) 9 – 10 0.4 0.5 0.6 V SB Pin Clamp Voltage VSB(CLAMP) 9 – 10 6.1 6.7 7.4 V SB Pin Source Current ISB(SRC) 9 – 10 − 20 − 10 − 4 µA SB Pin Sink Current ISB(SNK) 9 – 10 4 10 20 µA Overload Protection (OLP) with Input Voltage Compensation CL Pin Threshold Voltage (1) VCL1 VSPL = 1V 6 – 10 4.40 4.69 4.88 V CL Pin Threshold Voltage (2) VCL2 VSPL = 2V 6 – 10 3.05 3.43 3.65 V CL Pin Threshold Voltage (3) VCL3 VSPL = 4V 6 – 10 1.60 1.83 2.05 V CL Pin Threshold Voltage (4) VCL4 VSPL = 5V 6 – 10 1.05 1.29 1.55 V CL Pin Source Current ICL 6 – 10 − 29 − 17 − 5 μA Brown-In and Brown-Out VSEN Pin Threshold Voltage (On) VSEN(ON) 1 – 10 1.248 1.300 1.352 V VSEN Pin Threshold Voltage (Off) VSEN(OFF) 1 – 10 1.070 1.115 1.160 V VSEN Pin Clamp Voltage VSEN (CLAMP) 1 – 10 10.0 – – V VSPL Pin Clamp Voltage VSPL (CLAMP) 4 – 10 10.0 – – V Reset Detection Maximum Reset Time tRST(MAX) 11 – 10 16 − 15 4.0 5.0 6.0 µs Driver Circuit Power Supply VREG Pin Output Voltage VREG 12 – 10 9.6 10.4 11.2 V High-side Driver High-side Driver Operation Start Voltage VBUV(ON) 14 – 15 6.3 7.3 8.3 V High-side Driver Operation Stop Voltage VBUV(OFF) 14 – 15 5.5 6.4 7.2 V Driver Circuit VGL,VGH Pin Source Current 1 IGL(SRC)1 IGH(SRC)1 VREG = 10.5V VB = 10.5V VGL = 0V VGH = 0V 11 – 10 16 − 15 – – 540 – A VGL,VGH Pin Sink Current 1 IGL(SNK)1 IGH(SNK)1 VREG = 10.5V VB = 10.5V VGL = 10.5V VGH = 10.5V 11 – 10 16 − 15 – 1.50 – A VGL,VGH Pin Source Current 2 IGL(SRC)2 IGH(SRC)2 VREG = 12V VB = 12V VGL = 10.5V VGH = 10.5V 11 – 10 16 − 15 − 140 − 90 − 40 mA VGL,VGH Pin Sink Current 2 IGL(SNK)2 IGH(SNK)2 VREG = 12V VB = 12V VGL = 1.5V VGH = 1.5V 11 – 10 16 − 15 140 250 360 mA Current Resonant and Overcurrent Protection(OCP) Capacitive Mode Detection Voltage 1 VRC1 7 – 10 0.02 0.10 0.18 V

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 6 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 Characteristic Symbol Conditions Pins Min. Typ. Max. Unit Notes Capacitive Mode Detection Voltage 2 VRC2 7 – 10 0.35 0.50 0.65 V RC Pin Threshold Voltage (Low) VRC(L) 7 – 10 1.42 1.50 1.58 V RC Pin Threshold Voltage (High speed) VRC(S) 7 – 10 2.15 2.30 2.45 V CSS Pin Sink Current (Low) ICSS(L) 5 – 10 1.2 1.8 2.4 mA CSS Pin Sink Current (High speed) ICSS(S) 5 – 10 13.0 20.5 28.0 mA Overvoltage Protection (OVP) VCC Pin OVP Threshold Voltage VCC(OVP) 2 – 10 29.5 32.0 34.5 V Thermal Shutdown (TSD) Thermal Shutdown Temperature Tj(TSD) − 140 – – °C Thermal Resistance Junction to Ambient Thermal Resistance θj-A − − − 95 °C/W

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 7 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 3. Block Diagram STARTUP START/STOP/ REG/BIAS/ OVP MAIN INPUT SENSE STANDBY CONTROL FB CONTROL FREQ. CONTROL DEAD TIME UVLO LEVEL SHIFT OC DETECTOR dv/dt DETECTOR RC DETECTOR PL DETECTOR/ OLP FREQ. MAX SOFT-START/ OC/FMINADJ VCCGND ST 18 VCC GND VSEN SB FB CSS VB VGH VS REG VGL RC CL PL VSPL High Side Driver BD_SSC3S900_R2 4. Pin Configuration Definitions VCC FB VSPL CSS CL RC PL SB ST (NC) VGH VS VB (NC) REG VGL GND VSEN Number Name Function

1 VSEN The mains input voltage detection signal input

2 VCC Supply voltage input for the IC, and Overvoltage

Protection (OVP) signal input

3 FB Feedback signal input for constant voltage control

4 VSPL The input voltage detection signal input for OLP

Input Voltage Compensation

5 CSS Soft-start capacitor connection

6 CL OLP Input Voltage Compensation capacitor

7 RC Resonant current detection signal input, and

Overcurrent Protection (OCP) signal input

8 PL Resonant current detection signal input for OLP

Input Voltage Compensation

9 SB Standby mode change signal input

10 GND Ground

11 VGL Low-side gate drive output

12 REG Supply voltage output for gate drive circuit

13 (NC) −

14 VB Supply voltage input for high-side driver

15 VS Floating ground for high-side driver

16 VGH High-side gate drive output

17 (NC) −

18 ST Startup current input

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 8 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 5. Typical Application VSPL VSEN VCC FB ST NC VGH VS VB NC REG CSS CL PL VGL GND RC SB Standby VOUT2 GND VOUT1 PC1 PC2 PC1 PC2 SSC3S900 BR1 C1 R2 R3R4 ROCP R6 R7 R10 R11 R12 R13 R14 R15 R16 R17Q1 Q(H) Q(L) C9 C10 C11 C12 Ci CV D51 D52 D53 D54 C51 C52 C53 C54 C55 R51 R52 R53 R54R56 R55 R57 R58 R59 Q51 VAC Main Input R15 R16

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 9 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 6. External Dimensions

• SOP18 NOTES:
• Dimension is in millimeters
• Pb-free. Device composition compliant with the RoHS directive 7. Marking Diagram Part Number S S C 3 S 9 0 × X X X X Sanken Control Number Lot Number Y is the last digit of the year (0~9) M is the month (1~9, O, N or D) D is a period of days (1 ~ 3): 1 : 1st ~ 10th 2 : 11th ~ 20th 3 : 21th ~ 31st S K Y M D

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 10 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 8. Operational Description All of the parameter values used in these descriptions are typical values, unless they are specified as minimum or maximum. With regard to current direction, "+" indicates sink current (toward the IC) and " –" indicates source current (from the IC). Q(H) and Q(L) indicate a high-side power MOSFET and a low -side power MOSFET respectively. Ci, and CV indicate a current resonant capacitor and a voltage resonant capacitor respectively.

8.1 Resonant Circuit Operation

Figure 8-1 shows a basic RLC series resonant circuit. R L C Figure 8-1 RLC series resonant circuit The impedance of the circuit, Ż, is as the following Equation. (1) where, ω is angular frequency and ω = 2πf. (2) When the frequency , f, changes, the impedance of resonant circuit will change as shown in Figure 8-2 f0 Frequency Inductance areaCapacitance area Impedance R Figure 8-2 Impedance of resonant circuit In Equation (2), Ż becomes minimum value (= R) at 2πfL = 1/2πfC, and then ω is calculated by Equation (3) . (3) The frequency in which Ż becomes minimum value is the resonant frequency, f 0. T he higher frequency area than f 0 is the inductance area, and the lower frequency area than f0 is the capacitance area. From Equation (3), f0 is as follows; (4) Figure 8-3 shows the circuit of a current resonant power supply. The basic configuration of the current resonant power supply is a half -bridge converter. The switching device Q(H) and Q(L) are connected in series with V IN. The series resonant circuit and the v oltage resonant capacitor CV are connected in parallel with Q(L). The series resonant circuit is comprised of a resonant inductor L R, a primary winding P of a transformer T1 and a current resonant capacitor Ci. In the resonant transformer T1, the coupling between primary winding and secondary winding is designed to be poor so that the leakage inductance increases. By using it as LR, the series resonant circuit can be down sized. The dotted mark in T1 shows the winding polarity, the secondary windings S1 and S2 are connected so that the polarities are set to the same position shown in Figure 8-3, and the winding numbers of each other are equal. From Equation (1), the impedance of current resonant power supply is calculated by Equa tion (5). From Equation (4), the resonant frequency, f0, is calculated by Equation (6). (5) (6) where, R: the equivalent resistance of load LR: the inductance of the resonant inductor LP: the inductance of the primary winding P Ci: the capacitance of current resonant capacitor Cv Ci LR Q(H) P Series resonant circuit VOUT (+) (−) VIN VGH VGL Q(L) VDS(L) VDS(H) VCi ID(H) ID(L) ICi IS2 IS1 LP Figure 8-3 Current resonant power supply circuit

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 13 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013

8.2 Startup Operation

Figure 8-11 shows the VCC pin peripheral circuit. When the following all conditions are fulfilled, the IC starts the startup operation:

• The mains input voltage is provided, and the VSEN pin voltage incre ases to the on -threshold voltage, VSEN(ON) = 1.300 V, or more.
• The startup current, ICC(ST), which is a constant current of 6.0 mA, is provided from the IC to capacitor C2 connected to the VCC pin, C2 is charged, and the VCC pin voltage increases to the operation start voltage, VCC(ON) = 14.0 V, or more.
• The FB pin voltage increases to the oscillation start threshold voltage, VFB(ON) = 0.30 V, or more. After that, the startup circuit stops automatically, in order to eliminate its own power consumption. 5 10 CSS VCC GND VSPL R5 C2C6 VSEN ST VD Figure 8-11 VCC pin peripheral circuit During the IC operation, the rectified voltage from the auxiliary winding voltage, VD, of Figure 8-11 is a power source to the VCC pin. The winding turns of the winding D should be adjusted so that the VCC pin voltage is applied to equation (7) within the specification of the mains input voltage range and output load range of the power supply. The target voltage of the winding D is about 19 V. The startup time, t START, is determined by the value of C2 and C6 connected to the CSS pin. Since the startup time for C6 is much smaller than that for C2, the startup time is approximately given as below: (8) where: tSTART is the startup time in s, VCC(INT) is the initial voltage of the VCC pin in V, and ICC(ST) is the startup current, 6.0 mA

8.3 Undervoltage Lockout (UVLO)

Figure 8-12 shows the relationship of VCC and ICC. After the IC starts operation, when the VCC pin voltage decreases to V CC(OFF) = 9.8 V, the IC stops switching operation by the Undervoltage Lockout (UVLO) Function and reverts to the state before startup again. ICC VCC（OFF） VCC（ON） VCC pin voltage StartStop Figure 8-12 VCC versus ICC

8.4 Bias Assist Function

Figure 8-13 shows the VCC pin voltage behavior during the startup period. IC startup VCC pin voltage VCC(ON) VCC(BIAS) VCC(OFF) Startup failure Startup success Target operating voltage Time Bias Assist period Increasing by output voltage rising Figure 8-13 VCC pin voltage during startup period When the conditions of Section 8.2 are fulfilled, the IC starts operation. Thus, the circuit current, I CC, increases, and the VCC pin voltage begins dropping. At the same time, the auxiliary winding voltage, V D, increases in proportion to the output voltage rise. Thus, the VCC pin voltage is set by the balance between dropping due to the increase of I CC and rising due to the increase of the auxiliary winding voltage, V D. When the VCC pin voltage decreases to V CC(OFF) = 9.8 V, the IC stops switching operation and a startup failure occurs. In order to prevent thi s, when the VCC pin voltage decreases to the startup current threshold biasing voltage, VCC(BIAS) = 11.0 V, the Bias Assist Function is activated.

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 14 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 While the Bias Assist Function is activated, any decrease of the VCC pin voltage is counteracted by providing the startup current, I CC(ST), from the startup circuit. It is necessary to check the startup process based on actual operation in the application, and adjust the VCC pin voltage, so that the startup failure does not occur. If VCC pin voltage decreases to VCC(BIAS) and the Bias Assist Function is activated, the power loss increases. Thus, VCC pin voltage in normal operation should be set more than VCC(BIAS) by the following adjustments.

• The turns ratio of the auxiliary winding to the secondary-side winding is increased.
• The value of C2 in Figure 8-11 is increased and/or the value of R1 is reduced. During all protection operation, the Bias Assist Function is disabled.

8.5 Soft Start Function

Figure 8-14 shows the Soft -start operation waveforms. CSS pin voltage Primary-side winding current OCP limit C6 is charged by ICSS(C) Time Time Soft-start period OCP operation peropd Frequency control by feedback signal Figure 8-14 Soft-start operation The IC has Soft Start Function to redu ce stress of peripheral component and prevent the c apacitive mode operation. During the soft start operation , C6 connected to the CSS pin is charged by the CSS Pin Charge Current, ICSS(C) = − 105 μA. The o scillation frequency is varied by the CSS pin voltage. The switching frequency gradually decreases from f (MAX)SS1 = 500 kHz at most, according to the CSS pin voltage rise. At same time, output power increase s. When the output voltage increases, the IC is operated with an oscillation frequency controlled by feedback.

1 The maximum frequency during normal operation is

f(MAX) = 300 kHz. When the IC becomes any of the following conditions, C6 is discharged by the CSS Pin Reset Current, ICSS(R) = 1.8 mA.

• The VCC pin voltage decreases to the operation stop voltage, VCC(OFF) = 9.8 V, or less.
• The VSEN pin voltage decreases to the off -threshold voltage, VSEN(OFF) = 1.0 V, or less.
• Any of protection operations in protection mode (OVP, OLP or TSD) is activated.

8.6 Minimum and Maximum Switching

The minimum switching frequency is adjustable by the value of R5 (RCSS) connected to the CSS pin. The relationship of R5 (R CSS) and the externally adjusted minimum frequency, f (MIN)ADJ, is shown in Figure 8-15. The f(MIN)ADJ should be adjusted to more than the resonant frequency, f 0, under the condition of the minimum mains input voltage and the maximum output power. The maximum switching frequency, f MAX, is determined by the inductance and the capacitance of the resonant circuit. The fMAX should be adjusted to less than the maximum frequency, f(MAX) = 300 kHz. Figure 8-15 R5 (RCSS) versus f(MIN)ADJ

8.7 High-side Driver

Figure 8-16 shows a bootstrap circuit. The bootstrap circuit is for driving to Q (H) and is made by D 3, R12 and C12 between the REG pin and the VS pin. When Q(H) is OFF state and Q (L) is ON state, the VS pin voltage becomes about ground level and C 12 is charged from the REG pin. When the voltage of between the VB pin and the VS pin, V B-S, increases to V BUV(ON) = 7.3 V or more, an internal high -side drive circuit starts operation. When VB-S decreases to VBUV(OFF) = 6.4 V or less, its drive circuit stops operation. In case the both ends of C 12 and 20 30 40 50 60 70 f(M(N)ADJ (kHz) RCSS (kΩ)

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 15 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 D4 are short, the IC is protected by V BUV(OFF). D4 for protection against negative voltage of the VS pin

• D3 D3 shoul d be an ultrafast recovery diode of short recovery time and low reverse current. As for Sanken’s diode lineup, AG01A (VRM = 600 V) of UFRD series is recommended for the specification that the maximum mains input voltage is 265VAC.
• C11, C12, and R12 The values of C11, C12, and R12 are determined by total gate charge, Qg, of external MOSFET and voltage dip amount between the VB pin and the VS pin in the burst mode of the standby mode change. C11, C12, and R12 should be adjusted so that the voltage between th e VB pin and the VS is more than VBUV(ON) = 7.3 V by measuring the voltage with a high-voltage differential probe. The reference value of C11 is 0.47μF to 1 μF. The time constant of C12 and R12 should be less than 500 ns. The values of C12 and R22 are 0.047 μF to 0.1 μF, and 2.2 Ω to 10 Ω. C11 and C12 should be a film type or ceramic capacitor of low ESR and low leakage current.
• D4 D4 should be a Schottky diode of low forward voltage, VF, so that the voltage between the VB pin and the VS pin must not decrease to the absolute maximum ratings of −0.3 V or less. VGH VS VB REG VGL GND T115 R12 C11 C12 D4 Bootstrap circuit Q(H) Q(L) Cv Ci Figure 8-16 Bootstrap circuit

8.8 Constant Voltage Control Operation

Figure 8-17 shows the FB pin peripheral circuit. The FB pin is sunk the feedback current by the photo-coupler, PC1, connected to FB pin. As a result, since the oscillation frequency is controlled by the FB pin, the output voltage is controlled to constant voltage (in inductance area). The feedback current increases under slight load condition, and thus the FB pin volta ge decreases. While the FB pin voltage decreases to the oscillation stop threshold voltage, VFB(OFF) = 0.20 V, or less, the IC stops switching operation. This oper ation reduces switching loss, and prevents the increasing of the secondary output voltage. In Figure 8-17, R8 and C9 are for phase compensation adjustment, and C5 is for high frequency noise rejection. The secondary -side circuit should be designed so that the collector current of PC1 is more than 195 μA which is the absolute value of the maximum source current, IFB(MAX). Especially the current transfer ratio, CTR, of the photo coupler should be taken aging degradation into consideration. 3 10 FB GND PC1C9 Figure 8-17 FB pin peripheral circuit

8.9 Standby Function

The IC has the Standby Function in order to increase circuit efficiency in light load. When the Standby Function is activated, the IC operates in the burst oscillation mode as shown in Figure 8-18.The burst oscillation has periodic non -switching intervals. Thus, the burst mode reduces switching losses. Generally, to improve efficiency under light load conditions, the frequency of the burst mode becomes just a few kilohertz. In addition, the IC has the Soft -on and the Soft -off Function in order to suppress rapid and sharp fluctuation of the drain current during the burst mode. thus, the audible noises can be reduced (refer to Section 8.9.2). The operation of the IC changes to the standby operation by the external signal (refer to Section 8.9.1). Time Primary-side main winding current Non-switching period Switching period Soft-on Soft-off Figure 8-18 Standby waveform

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 16 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013

8.9.1 Standby Mode Changed by External

Figure 8-19 shows the standby mode change circuit with extern al signal. Figure 8-20 shows the standby change operation waveforms. When the standby terminal of Figure 8-19 is provided with the L signal, Q1 turns off, C10 connected to the SB pin is discharged by the sink current, ISB(SNK) = 10 µA, and the SB pin voltage decreases. When the SB pin voltage decrease to the SB Pin Oscillation Stop Threshold Voltage, VSB(OFF) = 0.5 V, the operation of the IC is changed to the standby mode. When SB pin voltage is V SB(OFF) = 0.5 V or le ss and FB pin voltage is Oscillation Stop Threshold Voltage VFB(OFF) = 0.20 V or less, the IC stops switching operation. When the standby terminal is provided with the H signal and the SB pin voltage increases to Standby Threshold Voltage VSB(STB) = 5.0 V or more, the IC returns to normal operation. Standby GND REG SBFB PC1 PC2 PC2Q1 R16 R17 R15 C10C5 R58 R59 Q51 C11 Figure 8-19 Standby mode change circuit Time Standby SB pin voltage Primary-side main winding current VSB(STB) Standby operation FB pin voltage VFB(OFF) Switching stop Discharging by ISB(SNK) VSB(OFF) H L H Figure 8-20 Standby change operation waveforms

8.9.2 Burst Oscillation Operation

In standby operation, the IC operates burst oscillation where the peak drain current is suppressed by Soft-on /Soft-off Function in order to reduce audible noise from transformer. During burst oscillation operation, the switching oscillation is controlled by SB pin voltage. Figure 8-21 shows the burst oscillation operation waveforms. Time Output voltage SB pin voltage Primary-side main winding current FB pin voltage VFB(OFF) Discharged by ISB(SNK) VFB(ON) VSB(OFF) VSB(ON) Output current Charged by ISB(SRC) Soft-offSoft-on Figure 8-21 Burst oscillation operation waveforms When the SB pin voltage decreases to VSB(OFF) = 0.5 V or less and the FB pin voltage decreases to VFB(OFF) = 0.20 V or less, the IC stops switching operation and the output voltage decreases. Since the output voltage decreases, the FB pin voltage increases. When the FB pin voltage increases to the oscillation start threshold voltage, VFB(ON) = 0.30 V, C10 is charged by ISB(SRC) = − 10 µA, and the SB pin voltage gradually increases. When the SB pin voltage increases to the oscillation start threshold voltage, VSB(ON) = 0.6 V, the IC resumes switching operation, controlling the frequency control by the SB pin voltage. Thus, the output voltage increases (Soft-on). After that, when FB pin voltage decrease to oscillation stop threshold voltage, VFB(OFF) = 0.20 V, C10 is discharged by I SB(SNK) = 10 µA and SB pin voltage decreases. When the SB pin voltage decreas es to VSB(OFF) again, the IC stops switching operation. Thus, the output voltage decreases (Soft-off). The SB pin discharge time in the Soft-on and Soft-off Function depends on C10. When the value of C10 increases, the Soft -on/Soft-off Function makes the p eak drain current suppressed, and makes the burst period longer. Thus, the output ripple voltage may increase and/or the VCC pin voltage may decrease.

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 17 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 If the VCC pin voltage decreases to VCC(BIAS) = 11.0 V, the Bias Assist Function is always activated , and it results in the increase of power loss (refer to Section 8.4). Thus, it is necessary to adjust the value of C10 while checking the input power, the output ripple voltage, and the VCC pin voltage. The reference value of C10 is about 0.001 μF to 0.1 μF.

8.10 Automatic Dead Time Adjustment

The dead time is the period when both the high -side and the low-side power MOSFETs are off. As shown in Figure 8-22, if the dead time is shorter than the voltage resonant period, the power MOSFET is turned on and off during the voltage resonant operation. In this case, the power MOSFET turned on and off in hard switching operation , and t he switching loss increases. The Automatic Dead Time Adjustment Function is the function that the ZVS (Zero Voltage Switching) operation of Q (H) and Q (L) is controlled automatically by the voltage resonant period detection of IC. The voltage resonant period is varied by the power supply specifications (input voltage and output pow er, etc.). However, the power supply with this function is unnecessary to adjust the dead time for each power supply specification. Q(H) D-S voltage, VDS(H) VGL VGH Voltage resonant period Loss increase by hard switching operation Dead time Figure 8-22 ZVS failure operation waveform As shown in Figure 8-23, the VS pin detects the dv/dt period of rising and falling of the voltage between drain and source of the low -side power MOSFET , VDS(L), and the IC sets its dead time to that period. This function controls so that the high -side and the low -side power MOSFETs are automatically switched to Zero Voltage Switching (ZVS) operation. This function operates in the period from td(MIN) = 0.35 µs to td(MAX) = 1.65 µs. In minimum output power at maximum input voltage and maximum output power at minimum input voltage, the ZCS (Zero Current Switching) operation of IC ( the drain current flows through the body diode is about 1 μs as shown in Figure 8-24), should be checked based on actual operation in the application. Cv Ci VS VGL VGH GND Main RV DETECTOR dv dt dt On OnOff VDS(L) Low-side, VDS(L) Dead time period Figure 8-23 VS pin and dead time period Q(H) drain current, ID(H) Flows through body diode about 1μs Figure 8-24 ZCS check point

8.11 Brown-In and Brown-Out Function

Figure 8-25 shows the VSEN pin peripheral circuit. This function detects the mains input voltage, and stops switching operation during low mains input voltage, to prevent exceeding input current and overheating. R2 to R4 set the detection voltage of this function. When the VCC pin voltage is higher than V CC(ON), t his function operates depending on the VSEN pin voltage as follows:

• When the VSEN pin voltage is more than V SEN (ON) = 1.300 V, the IC starts. When the VSEN pin voltage is less than V SEN (OFF) = 1.0 V, the IC stops switching operation.

10 GND

Figure 8-25 VSEN pin peripheral circuit

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 18 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 Given, the DC input voltage when the IC starts as VIN(ON), the DC input voltage when the switching operation of the IC stops as VIN(OFF). VIN(ON) is calculated by Equation (9). VIN(OFF) is calculated by Equation (10). Thus, t he relationship between V IN(ON) and V IN(OFF) is Equation (11). (9) (10) (11) The detection resistance is calculated from Equation (9) as follows: (12) Because R2 and R3 are applied high DC voltage and are high resistance, the following should be considered:

• Select a res istor designed against electromigration according to the requirement of the application, or
• Use a combination of resistors in series for that to reduce each applied voltage The reference value of R2 is about 10 MΩ. C4 shown in Figure 8-25 is for reducing ripple voltage of detection voltage and making delay time. The value is 0.1 µF or more, and the reference value is about 0.47 µF. The value of R 2, R3 and R4 and C 4 should be selected based on actual operation in the application.

8.12 Capacitive Mode Detection Function

The resonant power supply is operated in the inductance area shown in Figure 8-26. In the capacitance area, the power supply becomes the c apacitive mode operation (refer to Section 8.1). In order to prevent the operation, the minimum oscillation frequency is needed to be set higher than f 0 on each power supply specification. However, the IC has the c apacitive mode operatio n Detection Function kept the frequency higher than f0. Thus, the minimum oscillation frequency setting is unnecessary and the power supply design is easier. In addition, the ability of transformer is improved because the operating frequency can operate close to the resonant frequency, f0. Capacitance area Inductance area Operating area Impedance Resonant fresuency Hard switching Sift switching Uncontrollable operation Figure 8-26 Operating area of resonant power supply The resonant current is detected by the RC pin, and the IC prevents the capacitive mode operation. When the capacitive mode is detected, the C7 connected to CL pin is charged by I CL(SRC) = − 17 μA. When the CL pin voltage increases to V CL(OLP), the OLP is activated and the switching operation stops. During the OLP operation, the intermittent operation by UVLO is repeated (refer to Section 8.17). The detection voltage is changed to V RC1 = ±0.10 V or V RC2 = ± 0.50 V depending on the load as shown in Figure 8-28 and Figure 8-29. The Capaciti ve Mode Operation Detection Function operations as follows:

• Period in which the Q(H) is ON Figure 8-27 shows the RC pin waveform in the inductance area, and Figure 8-28 and Figure 8-29 shows the RC pin waveform in the capacitance area. In the inductance area , the RC pin voltage doesn’t cross the plus side detection voltage in the downward direction during the on period of Q (H) as shown in Figure 8-27. On the contrary, in the capacitance are a, the RC pin voltage crosses the plus side detection voltage in the downward direction. At this point, the capacitive mode operation is detected. Thus, Q(H) is turned off, and Q(L) is turned on , as shown in Figure 8-28 and Figure 8-29.
• Period in which the Q(L) is on Contrary to the above of Q (H), in the capacitance area, the RC pin voltage crosses the minus side detection voltage in the upward directiont during the on period of Q(L) At this point, the capacitive mode operation is detected. Thus, Q(L) is turned off and Q(H) is turned on. As above, since the capacitive mode operation is detected by pulse -by-pulse and the operating frequency is synchronized with the frequency of the capacitive

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 19 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 mode operation, and the capacitive mode operation is prevented. In addition to the adjusting method of R OCP, C3, and R6 in Section 8.16, ROCP, C3, and R6 should be adjusted so that the absolute value of the RC pin voltage increases to more than |V RC2| = 0.50 V under the condition caused the capacitive mode operation easily, such as startup, turning off the mains input voltage, or output shorted. The RC pin voltage must be within th e absolute maximum ratings of −6 to 6 V +VRC VDS(H) ON OFF RC pin voltage Figure 8-27 RC pin voltage in inductance area VDS(H) Capacitive mode operation detection ON OFF +VRC2 RC pin voltage +VRC1 Figure 8-28 High side capacitive mode detection in light load VDS(H) Capacitive mode operation detection ON OFF +VRC2 RC pin voltage +VRC1 Figure 8-29 High side capacitive mode detection in heavy load

8.13 Input Electrolytic Capacitor

Figure 8-30 shows an application that residual voltage of the input capacitor, C1, is reduced after turning off the mains input voltage. R2 is connected to the AC input lines through D7 and D8. Just after turning off the mains input voltage, the VSEN pin voltage decr eases to VSEN(OFF) = 1.0 V according to a short time of the time constant with R2 to R4 and C4, and C1 is discharged by the equivalent to ICC(ST) = 6.0 mA. GND VSEN

4 VSPL

Main input→Off D8 ST 6 mA (ICC(ST)) Figure 8-30 Input capacitor discharge

8.14 Reset Detection Function

The magnetizing current means the circulating current applied for resonant operation, and that flows only into the primary-side circuit. During the startup period when the feedback control for the output voltage is inactive, if the magnetizing current cannot be reset in the on -period because of unbalanced operation, negative current may flows just before a power MOSFET turns off, and hard switching may occur, and stresses of power MOSFET may increase. To prevent this hard switching, the IC incorporates the Reset Detection Function. Figure 8-32 shows the high -side operation and drain current waveform examples in normal resonant operation and reset failure op eration. Figure 8-31 shows the reset detection operation example at the high -side on-period. 0 VRC= +0.1V Expanded on-period ID(H) VGL pin voltage LowHigh Normal on-period tRST(MAX) = 5μs Reset failure waveform VGH pin voltage Turning-on in negative drain current Low High Figure 8-31 Reset detection operation example at high-side on-period

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 20 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 The Reset Detection Function extends the on -period until the absolute value of RC pin voltage, |V RC1|, increases to 0.10 V or more. Thus, this function prevents the hard switching operation. When the on -period reaches the maximum reset time, tRST(MAX) = 5.0 μs, the on-period expires at that moment, and the power MOSFET turns off (refer to Figure 8-31). ID(H) Cv Ci Lr Q(H) Q(L) Lp Cv Ci Lr Lp Cv Ci Lr Lp Cv Ci Lr Lp Cv Ci Lr Lp Cv Ci Lr Lp A B C E F 0Magnetizing current VDS(H)=0V VDS(H)=0V Turning on at VDS(L)= 0V results in soft-switching VDS(H)=0V VDS(H)=0V Turning on at VDS(L) >> 0V results in hard-switching Recovery current of body diode Point A Point B Point C Point D Point E Point F Off Off On Off Off Off Off Off On Off Off On D ID(H) Q(H) Q(L) Q(H) Q(L) Q(H) Q(L) Q(H) Q(L) Q(H) Q(L) ID(H) ID(H) ID(H) ID(H) ID(H) ○ Normal resonant operation ● Reset failure operation Figure 8-32 High-side operation and drain current waveform examples in normal resonant operation and in reset failure operation

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8.15 Overvoltage Protection (OVP)

When the voltage between the VCC pin and the GND pin is applied to the OVP threshold voltage, VCC(OVP) = 32.0 V, or more, the Overvoltage Protection (OVP) is activated. The IC has two operation types of OVP. One is the auto restart. The other is latched shutdown. When the auxiliary winding supplies the VCC pin voltage, the OVP is able to detect an excessive output voltage, such as when the detection circuit for output control is open in the secondary -side circuit because the VCC pin voltage is proportional to the output voltage. The output voltage of the secondary-side circuit at OVP operation, V OUT(OVP), is approximately given as below: (13) where, VOUT(NORMAL) : Output voltage in normal operation VCC(NORMAL): VCC pin voltage in normal operation

• Auto Restart Type: SSC3S901 Figure 8-33 shows the OVP operation waveforms of auto restart type. When the OVP is activated, the IC stops switching operation and VCC pin voltage decreases. When VCC pin voltage decreases to VCC(P.OFF) = 9.8 V, the OVP operation is released and the startup circuit is activated. When VCC pin voltage is increased to VCC(ON) = 14.0 V by startup current, the IC starts the switching operation. During the OVP operation, the intermittent operation by UVLO is repeated. When the fault condition is removed, the IC returns to normal operation automatically. VCC pin voltage VGH/VGL VCC(P.OFF) VCC(ON) VCC(OVP) Figure 8-33 Auto restart type OVP operation waveforms
• Latched Shutdown Type: SSC3S902 Figure 8-34 shows the OVP operation waveforms of latched shutdown type. When the OVP is activated, the IC stops switching operation at the latched state and VCC pin voltage decreases. When VCC pin voltag e decreases to VCC(OFF) = 9.8 V, the startup circuit is activated. When VCC pin voltage is increased to VCC(ON) = 14.0 V by startup current, the startup circuit is turned off and VCC pin voltage decreases. During the OVP operation, the latch state is kept by turning on/off of the startup circuit. The latched state is released by following condition: VCC pin voltage is decreased to VCC(L.OFF) = 7.8 V or less by turning off the input voltage, or VSEN pin voltage is decreased to VSEN(OFF) = 1.0 V or less. VCC pin voltage VGH/VGL VCC(OFF) VCC(ON) VCC(OVP) VCC(L.OFF) Input voltage turn off Release Latch mode Figure 8-34 Latched shutdown type OVP operation waveforms

8.16 Overcurrent Protection (OCP)

The Overcurrent Protection (OCP) detects the drain current, I D, on pulse -by-pulse basis, and limits output power. In Figure 8-35, this circuit enables the value of C3 for shunt capacitor to be smaller than the va lue of Ci for current resonant capacitor, and the detection current through C3 is small. Thus, the loss of the detection resistor, ROCP, is reduced, and R OCP is a small -sized one available. There is no convenient method to calculate the accurate resonan t current value according to the mains input and output conditions, and others. Thus, ROCP, C3, and C6 should be adjusted based on actual operation in the application. The following is a reference adjusting method of ROCP, C3, R6, and C8:

• C3 and ROCP C3 is 100pF to 330pF (around 1 % of Ci value). ROCP is around 100 Ω. Given the current of the high side power MOSFET at ON state as ID(H). ROCP is calculated Equation (14). The detection voltage of R OCP is used the detection of the capacitive mode operation (refer to Section 8.12). Therefore, setting of R OCP and C 3 should be taken account of both OCP and the c apacitive mode operation. (14)

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• R6 and C8 are for high frequency noise reduction. R6 is 100 Ω to 470 Ω. C6 is 100 pF to 1000 pF. PL Cv Ci VS VGL VGH GNDCSS U1 15 5 7 8 I(H) RC C6 ROCP Q(H) Q(L) Figure 8-35 RC pin peripheral circuit The OCP operation has two -step threshold voltage as follows:
• Step I, RC pin threshold voltage (Low), VRC(L): This step is active first. When the absolute value of the RC pin voltage increases to more than |VOC(L)| = 1.50 V, C6 connected to the CSS pin is discharged by I CSS(L) = 1.8 mA. Thus, the switching frequency increases, and the output power is limited. During discharging C6, when the absolute value of the RC pin voltage decre ases to |V RC(L)| or less, the discharge stops.
• Step II, RC pin thr eshold voltage (High-speed), VRC(S): This step is active second. When the absolute value of the RC pin voltage increases to more than |V RC(S) | = 2.30 V, the high -speed OCP is activated, and power MOSFETs reverse on and off. At the same time, C6 is discharged by I CSS(S) = 20.5 mA. Thus, the switching frequency quickly increases, and the output power is quickly limited. This step operates as protections for exceeding overcurrent, such as the output shorted. When the absolute value of the RC pin voltage decreas es to |V RC(S)| or less, the operation is changed to the above Step I. When OLP Input Voltage Compensation is used, CL pin voltage is needed to reach the threshold voltage of Overload Protection (OLP), VCL(OLP), in the state that RC pin voltage is less than VRC(L). Therefore, when output power increases, the OLP is activated (refer to Section 8.17). When the input voltage is constant like PFC output, OLP Input Voltage Compensation is unnecessary. Therefore, when output power increases, the above OCP operation (Step I and Step II ) is activated.

8.17 Overload Protection (OLP) with Input

8.17.1 Overload Protection (OLP)

When CL pin voltage becomes the threshold voltage of Overload Protection (OLP), V CL(OLP), the OLP is activated and the switching operation stops. V CL(OLP) is depended on the input voltage by OLP Input Voltage Compensation Function as shown in Section 0. The trigger of OLP is different according to the c ase with OLP Input Voltage Compensation Function or without it.

• Without OLP Input Voltage Compensation Function Figure 8-36 shows the OLP operation wav eforms. When the absolute value of RC pin voltage increases to |VRC(L)| = 1.50 V by increasing of output power, the overcurrent protection (OCP) is activated . After that, the C7 connected to CL pin is charged by I CL = − 17 μA. When the OCP state continues and CL pin voltage increases to VCL(OLP), the OLP is activated.
• With OLP Input Voltage Compensation Function CL pin voltage is needed to reach V CL(OLP) in the state that RC pin voltage is less than VRC(L). When CL pin voltage reaches V CL(OLP) in one of the following condition, the OLP is activated as shown in Figure 8-37. 1) The output power increases, CL pin voltage increases to VCL(OLP) which is constant. 2) The input voltage increases, V CL(OLP) depending on OLP Input Voltage Compensation decreases to CL pin voltage. VGH/VGL RC pin voltage CL pin voltage VRC(L) VRC(L) VCL(OLP) Charged by ICL Figure 8-36 OLP operation waveform without OLP Input Voltage Compensation Function

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8.17.2 OLP Input Voltage Compensation

In the case without OLP Input Voltage Compensation Function, when the absolute value of RC pin volta ge increases to |VRC(L)| = 1.50 V, the capacitor connected to CS pin is charged. When CS pin voltage increases to VCL(OLP), the OLP is activated (refer to Figure 8-36). In the constant voltage control of current resonant topology, when the input voltage increases, the resonant frequency increases, and the peak drain current decreases. Since |V RC(L)| is a fixed value, when output power increases at the constant rate, there are the output power difference at OLP operation in high and low input voltages as shown in Figure 8-40.In the universal mains input voltage, the output power at OLP operation is very large in the maximum input voltage, and component stresses are increased by heating. Therefore, the IC has OLP Input Voltage Compensation Function that the output power difference at OLP operation is limited in input voltages, and can realize power supply of universal mains input voltage (85 VAC to 265VAC). As shown in Figure 8-41, this function compensates the OLP threshold voltage, V CL(OLP), depending on input voltage, and is used so that CL pin voltage reaches VCL(OLP) in the state that RC pin vo ltage is less than VRC(L). VGH/VGL RC pin voltage CL pin voltage VRC(L) VRC(L) VCL(OLP) Input voltage Output power Output power difference that occurs by input voltage AC85V AC265V OLP active OLP active Figure 8-40 OLP operation waveforms according to input voltage (without OLP Input Voltage Compensation) VGH/VGL RC pin voltage CL pin voltage VRC(L) VRC(L) VCL(OLP) Input voltage Output power AC85V AC265V Output power difference that occurs by input voltage OLP active OLP active Figure 8-41 OLP operation waveforms according to input voltage (with OLP Input Voltage Compensation)

• PL Pin and CL Pin Setup: The primary-side winding current as shown in Figure 8-42 includes the mag netizing current not transferred to the secondary -side circuit, and the load current proportional to the output current. The current separated from the primary -side winding current by C3 flows to the PL pin. As shown in Figure 8-43, the primary -side winding current flows to the C7 connected to CL pin during the high side power MOSFET turning on. The magnetizing current becomes zero by charging and discharging. Only the load current is charged to C7. As a result, the CL pin voltage is proportional to the output current. On actual operation of the application, C7 connected to the CL pin should be adjusted so that ripple voltage of the CL pin reduces. R7 connected to the PL pin should be adjusted so that the OLP at the minimum mains input voltage is activated before the OCP limited by the low threshold voltage of OCP, VRC(L). The PL pin voltage and the CL pin voltage must be within the absolute maximum ratings of −0.3 to 6 V, by adjusting R7, in the OCP operation point at the minimum mains input voltage.
• VSPL Pin Setup: The VSPL pin detects the mains input voltage. Both V SPL and the setting voltage in Section 8.11 Brown-In and Brown-Out Function are determined by R2, R3, and R4. Both of them should be adjusted based on actual operation in the application.

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 25 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 PL Cv Ci C3 VS VGL VGH GND 7 8 RC ROCP Q(H) Q(L) CL VSEN Figure 8-42 the peripheral circuit of VSPL, PL, CL pin CL pin voltage CL pin source current ROCP voltage VGH pin voltage Proportional voltage to output current Load current Magnetizing current Figure 8-43 The waveforms of CL pin

• Relationship Between VCL(OLP) and VSPL: VCL(OLP) is OLP threshold voltage of CL pin. V SPL is VSPL pin voltage. There are relationship b etween VCL(OLP) and VSPL as shown in Figure 8-44. 0 1 2 3 4 5 6 VCL(OLP) (V) VSPL (V) Figure 8-44 VSPL pin voltage versus typical OLP threshold voltage, VCL(OLP)
• Without OLP Input Voltage Compensation Func - tion: Figure 8-45 shows the circuit that OLP Input Voltage Compensation Function is canceled. The resistance of between PL pin and GND pin is about 100 k Ω. The fixed VSPL pin voltage is about 3V, and should be adjusted by checking the heating of component in OLP operation. PL Cv Ci VS VGL VGH GND 7 8 RC ROCP About 100kΩ Q(H) Q(L) CL VSPL4 About Figure 8-45 The IC peripheral circuit without OLP Input Voltage Compensation Function

8.18 Thermal Shutdown (TSD)

When the junction temperature of the IC reach to the Thermal Shutdown Temperature T j(TSD) = 140 °C (min.), Thermal Shutdown (TSD) is activated.

• Auto Restart Type: SSC3S901 When the TSD is activated, the IC stops switching operation. When the VCC pin voltage is decreased to VCC(P.OFF) = 9.8 V or less and the junction temperature of the IC is decreased to less than Tj(TSD), the IC restarts. During the protection mode, restart and stop are repeated. When the fault condition is removed , the IC returns to normal operation automatically.
• Latched Shutdown Type: SSC3S902 When the TSD is activated, the IC stops switching operation at the latched state . During the TSD operation, the latch state is kept by turning on/off of the startup circuit (refer to Section 0). The latched state is released by following condition: VCC pin voltage is decreased to VCC(L.OFF) = 7.8 V or less by turning off the input voltage, or VSEN pin voltage is decreased to VSEN(OFF) = 1.0 V or less.

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 26 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 9. Design Notes

9.1 External Components

Take care to use the proper rating and proper type of components.

9.1.1 Input and output electrolytic

Apply proper derating to ripple current, voltage, and temperature rise. The e lectrolytic capacitor of high ripple current and low impedance types, designed for switch mode power supplies, is recommended to use.

9.1.2 Resonant transformer

The resonant power suppl y uses the leakage inductance of transformer. Therefore, in order to reduce the effect of the eddy current and the skin effect, the wire of transformer should be used a bundle of fine litz wires.

9.1.3 Current detection resistor, ROCP

Choose a type of low internal inductance because a high frequency switching current flows to R OCP, and of properly allowable dissipation.

9.1.4 Current resonant capacitor, Ci

Since large current flows into Ci, choose a capacitor of low loss and high allowable ripple current, such as polypropylene capacitor. In addition, Ci must be considered its frequency characteristic in order to flow high frequency current.

9.1.5 Gate Pin Peripheral Circuit

The VGH pin and the VGL pin are gate drive output pins for external power MOSFETs. The peak source current of both of them is – 540 mA, and the peak sink current is 1.50 A. DS of Figure 9-1 makes a turn-off speed faster. RA, RB and Ds should be adjusted considering power losses of power MOSFETs, gate waveforms (reduction of ringing caused by pattern layout and others), and EMI noise. RA is about 33 Ω to 330 Ω. RB is about 10 Ω. RGS prevents malfunctions caused by steep d v/dt at turning off power MOSFET. RGS is recommended to be a resistor of 10 k to 100 kΩ close to the Gate and the Source of power MOSFET. When the gate resistances are adjusted, the gate waveforms should be checked that the dead time is ensured as shown in Figure 9-2. DS RA RGS Drain Source Gate RB Figure 9-1 Power MOSFET peripheral circuit High-side Gate Low-side Gate Vth(min.) Vth(min.) Dead time Dead time Figure 9-2 Dead time confirmation

9.2 PCB Trace Layout and Component

The switching power supply circuit has the high frequency and high voltage traces. Since the PCB circuit design and the component layout significantly affect the power supply operation, EMI noise, and power dissipation, the high frequency trace of PCB shown in Figure 9-3 should be designed low impedance by small loop and wide trace. Figure 9-3 High frequency current loop (hatched areas)

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 29 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 11. Reference Design of Power Supply As an example, the following show the power supply specification, the circuit schematic, the bill of materials, and the transformer specification. The values in bill of materials are reference design. They are necessary to be adjusted based on actual operation in the application.

• Power supply specification IC SSC3S901 Input voltage (Output of PFC) DC 390 V Maximum output power 227.1 W Output 1 13 V / 6.7 A Output 2 100 V / 1.4A
• Circuit schematic PFC OUT D202 R213 C203 C104 R201 R202 R203 R204 R205 C204 R209 C205 C206 C207 R212 D205 R225 R221 C201 C212 C214 C215 C103 D203D204 R215 D206 C225 C209 R208 R200 C210 Q204 R218 R217 PC201 PC202 C216 C217 Q201 Q202 R206 C218 C202 R219 R214R211 R230 C211 P D CN601 R609C301 C308 R302 R301 R306 R307 R310 R303 C305 PC201 Q301 R304 C605 Q601 PC202 D601 R601 R602 R610 POWER_ ON/OFFC304 13V CN401 Q606 R614 R616 R615C606 8,9 R604 R305 Q602 D301 D302 CN602 R613 C302 C309 C604 100V S4 D304 D303 D602 R309 R308 J5//J7 J3//J8 J13 R210 J14 J18 R216 J1J9 J23 J11 R220 J12 J24 J33 J24 J33 J26 J20, J30, J32 C303 J21 J27 J31 J29 J28 VSEN CL RC VCC FB VSPL CSS PL SB IC201 SSC3S900 ST NC REG NC VGH VS VB VGL GND
• Bill of materials Symbol Part type Rating Recommended Sanken Parts C103 Electrolytic 450 V, 120 μF C104 Electrolytic 450 V, 120 μF C201 Chip 50 V, 0.1 μF, 2012 C202 Chip 50 V, 1.0 nF, 2012 C203 Ceramic Open C204 Chip 50 V, 2.2 nF, 2012 C205 Chip 50 V, 0.47 μF, 2012 C206 Chip 50 V, 0.22 μF, 2012 C207 Chip 50 V, 220 pF, 2012 C209 Chip 50 V, 0.22 μF, 2012 C210 Chip 50 V, 4.7 nF, 2012 C211 Ceramic 1 kV, 100 pF C212 Chip 50 V, 1 μF, 2012 C214 Ceramic 1 kV, 100 pF C215 Polypropylene Film 630 V, 27 nF C216 Ceramic, Y1 AC300 V, 2200 pF C217 Polypropylene Film Open C225 Electrolytic 50 V, 100 μF, C301 Electrolytic 35 V, 2200 μF C302 Electrolytic 200 V, 220 μF C303 Chip Open

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 30 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 Symbol Part type Rating Recommended Sanken Parts C304 Chip Open C305 Chip 50 V, 0.22 μF, 2012 C308 Electrolytic 35 V, 2200 μF C309 Electrolytic Open C604 Electrolytic Open C605 Electrolytic Open C606 Chip Open D202 Schottky 40 V, 1 A, SJP SJPB-D4 D203 Schottky 40 V, 1 A, SJP SJPB-D4 D204 Fast recovery 600 V, 0.5 A, Axial AG01A D205 Schottky 40 V, 1 A, SJP SJPB-D4 D206 Fast recovery 200 V, 1 A, Axial AL01Z D301 Schottky 150 V, 30 A, TO220F FMEN-230A D302 Schottky 150 V, 30 A, TO220F FMEN-230A D303 Fast recovery 200 V, 5 A, TO220F FML-14S D304 Fast recovery 200 V, 5 A, TO220F FML-14S D601 Schottky 40 V, 1 A, SJP SJPB-D4 D602 Chip 0Ω ± 5 %, 1/8 W, 2012 IC201 IC SSC3S901 PC201 Photo-coupler PC123 or equiv PC202 Photo-coupler PC123 or equiv Q201 Power MOSFET 10 A, 600 V, TO220 Q202 Power MOSFET 10 A, 600 V, TO220 Q204 PNP transistor –600 mA, –60 V, SOT23 KST2907A Q301 Shunt regulator VREF = 2.50 V (TL431or equiv) Q601 PNP transistor 0.6A, – 60V, SOT23 Q602 NPN transistor 0.6 A, 40 V, SOT23 Q606 NPN transistor 0.8 A, 60 V SOT-23/TO-92 R200 Chip 47 kΩ ± 5 %, 1/4 W, 3216 R201* Chip 1.0 MΩ ± 5 %, 1/4 W, 3216 R202* Chip 1.0 MΩ ± 5 %, 1/4 W, 3216 R203* Chip 1.0 MΩ ± 5 %, 1/4 W, 3216 R204* Chip 910 kΩ + 47 kΩ ± 5 %, 1/4 W, 3216 R205 Chip 680 Ω ± 5 %, 1/8 W, 2012 R206 Chip 0 Ω ± 5 %, 1/4 W, 3216 R208 Chip 22 kΩ ± 5 %, 1/8 W, 2012 R209 Chip 47 kΩ ± 5 %, 1/8 W, 2012 R210 Chip 100 Ω ± 5 %, 1/8 W, 2012 R211 Chip 2.2 Ω ± 5 %, 1/8 W, 2012 R212 Chip 33 kΩ ± 5 %, 1/8 W, 2012 R213 Chip 100 Ω ± 5 %, 1/8 W, 2012 R214 Chip 10 kΩ ± 5 %, 1/8 W, 2012 R215 Chip 2.2 Ω ± 5 %, 1/8 W, 2012 R216 Chip 47 kΩ ± 5 %, 1/8 W, 2012 R217 Chip 22 kΩ ± 5 %, 1/8 W, 2012 R218 Chip 100 kΩ ± 5 %, 1/8 W, 2012 R219 Chip 2.2 Ω ± 5 %, 1/8 W, 2012 R220 Chip 10 kΩ ± 5 %, 1/8 W, 2012 R221 Chip 100 kΩ ± 5 %, 1/8 W, 2012 R225 Chip 150 Ω ± 5 %, 1/8 W, 2012 R230 Chip 100 Ω ± 5 %, 1/8 W, 2012 * Resistors applied high DC voltage and of high resistance are recommended to select resistors designed against electromigration or use combinations of resistors in series for that to reduce each applied voltage, according to the requirement of the application.

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 31 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 Symbol Part type Rating Recommended Sanken Parts R301 Chip 5.6 kΩ ± 5 %, 1/8 W, 2012 R302 Chip 4.7 kΩ ± 5 %, 1/8 W, 2012 R303 Chip 10 kΩ ± 5 %, 1/8 W, 2012 R304 Chip 2.2 kΩ ± 5 %, 1/8 W, 2012 R305 Chip Open R306 Chip 22 kΩ ± 5 %, 1/8 W, 2012 R307 Chip 20 kΩ ± 5 %, 1/8 W, 2012 R308* Chip Open R309* Chip Open R310 Chip 15 kΩ ± 5 % , 1/8 W, 2012 R601 Chip 1 kΩ ± 5 %, 1/10 W, 2012 R602 Chip 2.2 kΩ ± 5 %, 1/8 W, 2012 R604 Chip 4.7kΩ ± 5 %, 1/8 W, 2012 R609 Chip Open R610 Chip Open R613* Chip Open R614 Chip 22 kΩ+4.7 kΩ ± 5 %, 1/8 W, 2012 R615 Chip Open R616 Chip 0 Ω ± 5 %, 1/8 W, 2012 T1 See the specification * Resistors applied high DC voltage and of high resistance are recommended to select resistors designed against electromigration or use combinations of resistors in series for that to reduce each applied voltage, according to the requirement of the application.

• Transformer specification Primary inductance, LP : 250 μH Leakage inductance, Lr : 80 μH Core size : EER-42
• Winding specification Winding Symbol Number of turns (T) Wire diameter (mm) Construction Primary winding Lp 33 Litz φ0.1 mm 30 strands Solenoid winding Auxiliary winding D 3 TIW φ0.2 mm Space winding Output winding 1-1 S1-1 2 Litz φ0.1 mm 70 strands Bifilar winding Output winding 1-2 S1-2 2 Litz φ0.1 mm 70 strands Bifilar winding Output winding 2-1 S2-1 15 Litz φ0.1 mm 30 strands Bifilar winding Output winding 2-2 S2-2 15 Litz φ0.1 mm 30 strands Bifilar winding Bobbin D S2-1 Lp (1) (3) (4) S2-2 : Start at this pin Cross-section view Bobbin D Lp Primary side Secondary side S1-1, S1-2 S2-1, S2-2 Core side (2) (12) (11) (11) (10) S1-1 S1-2 (8) (7) (6) (5) VS C215//C217 VCC GND VOUT1(+) VOUT1(+) VOUT1(-) VOUT1(-) VOUT2(+) VOUT2(+) VOUT2(-) VOUT2(-) Core side

SSC3S900 - DSJ Rev.2.4 SANKEN ELECTRIC CO.,LTD. 32 Apr. 01, 2016 http://www.sanken-ele.co.jp © SANKEN ELECTRIC CO.,LTD. 2013 IMPORTANT NOTES

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• Please refer to the relevant specification documents in relation to particular precautions when using the Sanken Products, and refer to our official website in relation to general instructions and directions for using the Sanken Products. DSGN-CEZ-16001