SC2569 ETC
Document overview
- Manufacturer or author: Provided By www.digicamel.com(free datasheet download site)
- PDF pages: 13
Technical content
Features
◆ Extended Burst Mode Control For Improved Efficiency and Minimum Standby Power Design ◆ Power-on Soft Start Reducing MOS Stress ◆ Audio Noise Free Operation ◆ External Programmable PWM Switching Frequency ◆ Low VDD startup and operating current ◆ Frequency jitter to Minimize EMI ◆ Leading edge blanking on current sense ◆ Internal Synchronized Slope Compensation ◆ Low VIN/VDD Startup Current(6.5uA) and Low Operating Current(2.0mA) ◆ Complete Protection Coverage With Auto Self-Recovery ⚫ VDD Under Voltage Lockout with Hysteresis (UVLO) ⚫ Cycle-by-Cycle over current Protection ⚫ Over load Protection (OLP) ⚫ Over Temperature Protection (OTP) ⚫ VDD Over Voltage Protection (OVP)
Applications
Offline AC/DC flyback converter for ◆ AC/DC Adapter ◆ Set-Top Box Power Supplies ◆ Auxiliary Power Supply ◆ Open-frame SMPS ◆ Battery Charger
High Performance Current Mode PWM Controller © Safety-Chip Micro 2 www.safety-chip.com SC2569_Datasheet_V1.0_EN Typical Application EMI Filter AC IN DC Out RI GATE VIN GND SENSE 3 6 7FB2 4 5 VDD RT NTC Pin Configuration DIP-8 (TOP VIEW) SOP-8 (TOP VIEW) GATE VDD RT RIFBGND VIN SENSE TOP MARK YYWWPPXWWY TOP MARK GATE VDD RT RIFBGND VIN SENSE TOP MARK YYWWPPXWWY TOP MARK X: A or B or Blank Y: Year Code WW: Week Code(01-52)
Ordering Information
Part number Package TOP MARK Shipping SC2569 DIP-8/SOP-8 Pb-free SC2569 Tape & Reel
© Safety-Chip Micro 3 www.safety-chip.com SC2569_Datasheet_V1.0_EN Block Diagram OVP Vref UVLO PWM Logic Soft Driver LEB Slope Compensation Green Mode VDD SENSEGND FB GATE Burst Mode Vocp Regulator Chip OTP Soft Start OLP VDD RT OTP RI Voltage/Current Reference VIN3 OCP Threshold Line Compensation
© Safety-Chip Micro 4 www.safety-chip.com SC2569_Datasheet_V1.0_EN Pin Descriptions Name Pin I/O Description GND 1 P Ground FB 2 I Feedback input pin. PWM duty cycle is determined by voltage level into this pin and current-sense signal level at Pin 6. VIN 3 I Connected through a large value resistor to rectified line input for Startup IC supply and line voltage sensing. RI 4 I Internal Oscillator frequency setting pin. A resistor connected between RI and GND sets the PWM frequency. RT 5 I Temperature sensing input pin. Connected through a NTC resistor to GND. SENSE 6 I Current sense input. Connected to MOSFET current sensing resistor node. VDD 7 P DC Power Supply pin. GATE 8 O Totem-pole gate drive output for power MOSFET. Absolute Maximum Ratings Symbol Parameter Min. Max. Unit VDD/VIN DC Supply Voltage 28 V VDD_Clamp VDD Clamp Voltage 30 V IDD_Clamp VDD Clamp Continuous Current 10 mA VFB FB Input Voltage -0.3V 6.5 V VSENSE SENSE Input Voltage -0.3V 6.5 V VRT RT Input Voltage -0.3V 6.5 V VRI RI Input Voltage -0.3V 6.5 V RJA SOP-8 Thermal Resistance (Junction-to-Air) 120 ℃/W TJ Operating Junction Temperature -20 125 ℃ TSTG Storage Temperature Range -55 150 ℃ TL Lead Temperature (Wave Soldering or IR,10Seconds) 260 ℃ ESD Human Body Model,JEDEC:JESD22-A114 2.5 KV Machine Model, JEDEC:JESD22- A115 250 V Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute maximum -rated conditions for extended period may affect device’s reliability. Recommended Operating Conditions Symbol Parameter Min. Max. Unit VDD DC Supply Voltage 12 23 V TA Operating Ambient Temperature -20 85 ℃ RI RI Resistor Value 24 31 KΩ Maximum practical continuous power in an open frame design with sufficient drain pattern as a heat sink, at 45℃ ambient. Higher output power is possible with extra added heat sink or air circulation to reduce thermal resistance.
© Safety-Chip Micro 5 www.safety-chip.com SC2569_Datasheet_V1.0_EN Electrical Characteristics(TA = 25℃, VDD=16V, RI=24KΩ unless otherwise noted) Symbol Parameter Conditions Min. Typ. Max. Unit Supply Voltage (VDD) IDD_ST Startup Current VDD=15V 6.5 20 uA IDD_OP Operation Current VFB=3V 2.0 mA VDD_ON Threshold Voltage to Startup VDD Rising 14.5 15.5 16.5 V VDD_OFF Threshold Voltage to Stop Switching in Normal Mode VDD Falling 8.5 9.5 10.5 V VDD_OVP_ON VDD Over voltage protection Enter 23.5 25.0 26.5 V VDD_OVP_OFF VDD Over voltage protection Exit (Recovery) 21.5 23.0 24.5 V VDD_OVP_Hys OVP Hysteresis 2.0 V TD_VDD_OVP VDD OVP Debounce time 80 uSec VDD_Clamp VDD Zener Clamp voltage IVDD=5mA 30.0 V Feedback Input Section(FB Pin) VFB_Open FB Open Loop Voltage 5.1 V AV PWM input gain ΔVFB/ ΔVCS 2.8 V/V DMAX Max duty cycle VFB=3V,VCS=0.3V 75 80 85 % VRef_Green The threshold enter green mode 2.3 V VRef_Burst_H The threshold exit Burst mode 1.5 V VRef_Burst _L The threshold enter Burst mode 1.4 V IFB_Short FB pin short circuit current Short FB pin to GND 0.8 mA VTH_PL Power Limiting FB Threshold Voltage 4.4 V TD_PL Power limiting Debounce Time 75 mS ZFB_IN Input Impedance 6.9 KΩ Current Sense Input(SENSE Pin) TSS Soft start time 4 ms TLEB Leading edge blanking time 250 ns TD_OC Over Current Detection and Control Delay 120 ns VTH_OC_0 Current Limiting Threshold Voltage at No Compensation IVIN=0uA 0.85 0.9 0.95 V VTH_OC_1 Current Limiting Threshold Voltage at Compensation IVIN=150uA 0.81 V Oscillator FOSC Normal Oscillation Frequency VFB=3V, VCS=0V 60 65 70 KHz FJR Frequency jitter range +/-5 % FJitter jitter frequency 65 Hz FDT Frequency Variation vs. 5 %
© Safety-Chip Micro 6 www.safety-chip.com SC2569_Datasheet_V1.0_EN Symbol Parameter Conditions Min. Typ. Max. Unit Temperature Deviation FDV Frequency Variation vs. V DD Deviation 1 % RI_range Operating RI Range 12 24 60 KΩ VRI_open RI open voltage 2.0 V FBurst Burst Mode Switch Frequency 22 KHz Gate Driver Output VOL Output Low Level IO= -20mA 0.3 V VOH Output High Level IO= +20mA 11 V VGATE_CLAMP Output Clamp Voltage Level VDD=20V 18 V T_r Output Rising Time CL=1nf 120 nSec T_f Output Falling Time CL=1nf 50 nSec Over Temperature Protection IRT Output Current of RT Pin 70 uA VTH_OTP OTP Threshold Voltage 1.00 1.05 1.10 V VTH_OTP_OFF OTP Recovery Threshold Voltage 1.15 V TD_OTP OTP Debounce Time 100 uSec VRT_OPEN RT Pin Open Voltage 5.5 V
© Safety-Chip Micro 7 www.safety-chip.com SC2569_Datasheet_V1.0_EN Typical Performance Characteristics(TA = 25℃, VDD=16V, unless otherwise noted) 0.0 1.0 2.0 -20 0 20 40 60 80 100 120 140 IDD_ST(uA) Temperature(℃) IDD_ST vs. Temperature 1.0 1.5 2.0 2.5 -20 0 20 40 60 80 100 120 140 IDD_OP(mA) Temperature(℃) IDD_OP vs. Temperature 15.0 15.5 16.0 16.5 17.0 -20 0 20 40 60 80 100 120 140 VDD_ON(V) Temperature(℃) VDD_ON vs. Temperature 9.5 10.0 10.5 11.0 11.5 -20 0 20 40 60 80 100 120 140 VDD_OFF(V) Temperature(℃) VDD_OFF vs. Temperature 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0 2 4 6 8 10 12 14 16 18 20 22 24 VDD Current(mA) VDD Voltage(V) VDD UVLO and Operation Current 24.5 25.0 25.5 26.0 26.5 -20 0 20 40 60 80 100 120 140 VDD_OVP(V) Temperature(℃) VDD_OVP vs. Temperature
© Safety-Chip Micro 8 www.safety-chip.com SC2569_Datasheet_V1.0_EN 20.00 50.00 80.00 110.00 140.00 12 24 36 48 60 Fosc(KHz) RI(Kohm) Fosc（KHz)vs. R I(Kohm) -20 0 20 40 60 80 100 120 140 FOSC(KHz) Temperature(℃) FOSC vs. Temperature 0.88 0.89 0.90 0.91 0.92 -20 0 20 40 60 80 100 120 140 VTH_OC(V) Temperature(℃) VTH_OC vs. Temperature 0.70 0.75 0.80 0.85 0.90 0.95 0 50 100 150 200 250 300 VTH_OC(V) I(Vin)uA) VTH_OC vs. I(Vin) 67.0 67.5 68.0 68.5 69.0 69.5 70.0 70.5 71.0 71.5 72.0 -20 0 20 40 60 80 100 120 140 I_RT(uA) Temperature(℃) I_RT vs. Temperature
© Safety-Chip Micro 9 www.safety-chip.com SC2569_Datasheet_V1.0_EN Functional Description The SC2569 is a highly integrated PWM controller IC optimized for off -line flyback converter applications. The extended Burst Mode control greatly reduces the standby power consumption and helps the design easily to meet the international power conservation requirements. Startup Current and Start up Control Startup current of SC2569 is designed to be very low so that VDD could be charged up above VDD_ON and device starts up quickly. A large value startup resistor can therefore be used to minimize the power loss yet achieve a reliable startup in application. For a typical AC/DC adapto r with universal input range design, a 2M Ω, 1/8W startup resistor could be used together with a VDD capacitor to provide a fast startup and yet low power dissipation design solution. Operating Current The Operating current of SC2569 is low at 2.0mA (typical). Good efficiency is achieved with SC2569 low operation current together with the extended Burst Mode control features. Soft Start SC2569 features an internal 4ms (typical) soft start to soften the electrical stress occurring in the power supply during startup. It is activated during the power on sequence. As soon as VDD reaches VDD_ON, the SENSE peak voltage is gradually increased from 0.1V to the maximum level. Every restart up is followed by a soft start. Frequency jitter for EMI improvement The frequency jitter is implemented in SC2569. The oscillation frequency is modulated so that the tone energy is spread out. The spread spectrum minimizes the conduction band EMI and therefore eases the system design. Oscillator Operation The switching fre quency of SC2569 is externally programmable. A resistor connected between RI and GND sets the constant current source to charge/discharge the internal cap and thus the PWM oscillator frequency is determined. The relationship between RI and switching freque ncy follows the below equation within the specified RI in K Ω range at nominal loading operational condition. (Khz)KΩ(RI 1560=FOSC Multi-mode Operation for High Efficiency SC2569 is a multi-mode controller. The controller changes the mode of operation acc ording to the FB pin voltage. At the normal operating condition, the IC operates in （65KHz, if RI=24K Ω）PWM mode. As the output load current is decreased, the IC enter into green mode smoothly from the PWM mode. In this mode, the switching frequency will st art to linearly decrease from 65KHz to 22KHz. So the switching loss is minimized and the high conversion efficiency can be achieved. At light load or no load condition, most of the power dissipation in a switching mode power supply is from switching loss o f the MOSFET, the core loss of the transformer and the loss of the snubber circuit. The magnitude of power loss is in proportion to the switching frequency. Lower switching frequency leads to the reduction on the power loss and thus conserves the energy. The switching frequency is internally adjusted at no load or light load condition. The switch frequency reduces at light/no load condition to improve the conversion efficiency. At light load or no load condition, the FB input drops below VRef_Burst_L and device enters Burst Mode control. The Gate drive output switches when FB input rises back to VRef_Burst_H. Otherwise the gate drive remains at off state to minimize the switching loss and reduces the standby power consumption to the greatest extend. Current Sensing and Leading Edge Blanking Cycle-by-Cycle current limiting is offered in
© Safety-Chip Micro 10 www.safety-chip.com SC2569_Datasheet_V1.0_EN SC2569 current mode PWM control. The switch current is detected by a sense resistor into the SENSE pin. An internal leading edge blanking circuit chops off the sensed voltage spike at initial internal power MOSFET on state due to snubber diode reverse recovery and surge gate current of power MOSFET. The current limiting compar ator is disabled and cannot turn off the internal power MOSFET during the blanking period. The PW M duty cycle is determined by the current sense input voltage and the FB input voltage. Internal Synchronized Slope Compensation Built-in slope compensation circuit adds voltage ramp onto the current sense input voltage for PWM generation. This greatly improves the close loop stability at CCM and prevents the sub-harmonic oscillation and thus reduces the output ripple voltage. Over Temperature Protection A NTC resistor in series with a regular resistor should connect between RT and GND for temperature sensing and protection. NTC resistor value becomes lower when the ambient temperatures rise. With the fixed internal current IRT flowing through the resistors, the voltage at RT pin becomes lower at high temperature. The internal OTP circuit is triggered and shutdown the MOSFET when the sensed input voltage is lower than VTH_OTP. Gate Drive SC2269 GATE is connected to the gate of an external MOSFET for power switch control. Too weak the gate drive strength results in higher conduction and switch loss of MOSFET while too strong gate drive output compromises the EMI. A good trade -off is achieved through the built -in totem pole gate design with right output strength and dead time control. The low idle loss and good EMI system design is easier to achieve with this dedicated control scheme. An internal 18V clamp is added for MOSFET gate protection at higher than expected VDD input. Protection Controls Good power supply system reliability is achieved with auto -recovery protection features including Cycle-by-Cycle curre nt limiting (OCP), Under Voltage Lockout on VDD (UVLO), Over Temperature Protection (OTP), VDD Over Voltage Protection (OVP). The OCP threshold value is self adjusted lower at higher current into VIN pin. This OCP threshold slope adjustment helps to compen sate the increased output power limit at higher AC voltage caused by inherent Over -Current sensing and control delay. A constant output power limit is achieved with recommended OCP compensation scheme on SC2569. At output overload condition when FB input voltage exceeds power limit threshold value for more than TD_PL, control circuit reacts to shut down the power MOSFET. It restarts when VDD voltage drops below UVLO limit. Similarly, when an Over Temperature condition is detected, control circuit shutdowns the power MOSFET. SC2569 resumes the operation when temperature drops below the hysteresis value. VDD is supplied with transformer auxiliary winding output. It is clamped when VDD is higher than 35V. MOSFET is shut down when VDD drops below VDD_ON limit and device enters power on startup sequence thereafter.
© Safety-Chip Micro 11 www.safety-chip.com SC2569_Datasheet_V1.0_EN
Package Information
E D AL B1 B e A2A1 C Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 3.710 4.310 0.146 0.170 A1 0.510 0.020 A2 3.200 3.600 0.126 0.142 B 0.360 0.560 0.014 0.022 B1 1.524(TYP) 0.060(TYP) C 0.204 0.360 0.008 0.014 D 9.000 9.400 0.354 0.370 E 6.200 6.600 0.244 0.260 E1 7.620(TYP) 0.300(TYP) E 2.540(TYP) 0.100(TYP) L 3.000 3.600 0.118 0.142 E2 8.200 9.400 0.323 0.370
© Safety-Chip Micro 12 www.safety-chip.com SC2569_Datasheet_V1.0_EN 8-Pin Plastic SOP-8 TOP VIEW RECOMMENDED LAND PATTERN FRONT VIEW SIDE VIEW 4.70 5.15 3.80 4.00 5.80 6.20 0.31 0.51 1.27 BSC 1.25 1.65 0.05 0.25 1.35 1.75 0.17 0.250.40 1.27 0.0° 8.0° 5.60 TYP 1.27 BSC 0.65 TYP 1.75 TYP Note: 1. All dimensions are in millimeters 2. Package length does not include mold flash protrusion or gate burr 3. Package WIDTH does not include mold flash protrusion 4. Drawing is not to scale
© Safety-Chip Micro 13 www.safety-chip.com SC2569_Datasheet_V1.0_EN Important Notice Right to Make Changes Safety-Chip Micro reserves the right to make corrections, modifications, enhancements, improvements and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. Warranty Information Safety-Chip Micro warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with its standard warranty. Testing and other quality control techniques are used to the extent it deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. Safety-Chip Micro assumes no liability for application assistance or customer product design. Cus tomers are responsible for their products and applications using Safety-Chip’s components, data sheet and application notes. To minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. Life Support Safety-Chip’s products are not designed to be used as components in devices intended to support or sustain human life. Safety-Chip Micro will not be held liable for any damages or claims resulting from the use of its products in medical applications. Military and Aerospace Safety-Chip’s products are not designed for use in Military and Aerospace applications. Safety-Chip Micro will not be held liable for any damages or claims resulting from the use of its products in Military and Aerospace applications.