AN8015SH PANASONIC
Document overview
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Technical content
Single-channel step-down, step-up, or inverting use DC-DC converter control IC n Overview The AN8015SH is a single-channel DC-DC converter control IC using the PWM method. This IC can provide any one output type from among step-down, step-up and inverting output. Its operating supply voltage range is wide and its consumption current is small. In addition, since it uses the 10-pin surface mounting type package with 0.5 mm pitch, it is suitable for highly efficient miniature potable power supply, especially for a negative output power supply. n Features
- Wide operating supply voltage range (3.6 V to 34 V)
- Small consumption current (1.8 mA typical)
- Converter control in a wide output frequency range is possible (2 kHz to 500 kHz).
- Built-in timer latch short-circuit protection circuit (charge current 1.1 mA typical)
- Incorporating the under-voltage lock-out (U.V.L.O.) circuit
- Incorporating a high precision reference voltage circuit (2.46 V (allowance: – 3%))
- Output block is open-collector (darlington) type.
- High absolute maximum rating of output current (100 mA)
- Maximum duty ratio is fixed and has small sample-to-sample variations (90% – 5%).
- Using 10-pin small outline package of 0.5 mm pitch n Applications
- LCD displays, digital still cameras, and PDAs n Block Diagram SSOP010-P-0225 Unit: mm 4.3–0.30 6.3–0.30 0.5–0.2 0.1–0.1 0.2–0.1 0.5 3.0–0.30 1.5–0.2 0.15 +0.1 –0.05 2.46 V (allowance : – 3%) Out5 GND4 IN+ 8 V CC V REF CT1 RT2 S.C.P. 3 Latch SR U.V .L.O. RO Triangular wave OSC Reference supply Clamp 1.11 V V REFI PWM comparator 1.2 V 0.5 V 0.37 V 1.83 V IN- 9 FB 10
AN8015SH Voltage Regulators n Pin Descriptions Pin No. Symbol Description
1 CT Pin for connecting oscillator timing capacitor
2 RT Pin for connecting oscillator timing resistor
3 S.C.P. Pin for connecting the time constant setting capacitor for short-circuit protection
4 GND Grounding pin
5 Out Open collector type output pin
6V CC Power supply voltage application pin 7V REF Reference voltage output pin 8I N + Error amplifier noninverted input pin 9I N - Error amplifier inverted input pin
10 FB Output pin of error amplifier
n Absolute Maximum Ratings Parameter Symbol Rating Unit Supply voltage V CC 35 V IN- terminal allowable application voltage VIN- - 0.3 to VREF IN+ terminal allowable application voltage VIN+ - 0.3 to VREF Output terminal allowable application voltage VOUT 35 Collector output current I OUT 100 mA Power dissipation * PD 154 mW Operating ambient temperature * T opr -30 to +85 °C Storage temperature * T stg -55 to +150 °C n Recommended Operating Range Parameter Symbol Range Unit Error amplifier input voltage V IN - 0.1 to 0.8 V Collector output voltage V OUT 34 (maximum) V Collector output current I OUT 50 (maximum) mA Timing capacitance C T 100 to 27 000 pF Timing resistance R T 5.6 to 15 k W Oscillation frequency f OUT 2 to 500 kHz Reference voltage output current I RE -3 to 0 mA Soft start short-circuit protection time CSCP 1 000 (minimum) pF constant setting capacitance Note) *: Expect for the power dissipation, operating ambient temperature, and storage temperature, all ratings are for Ta = 25°C.
Voltage Regulators AN8015SH n Electrical Characteristics at VCC = 12 V, RT = 15 W , CT = 200 pF, Ta = 25°C Parameter Symbol Conditions Min Typ Max Unit Reference voltage block Reference voltage V REF IREF = -1 mA 2.386 2.46 2.534 V Input regulation with input fluctuationLine V CC = 3.6 V to 34 V, IREF = -1 mA ¾ 52 0 m V Input regulation with input fluctuation 2Line2 V CC = 3.6 V to 20 V ¾¾ 10 mV Load regulation Load I REF = - 0.1 mA to -1 mA ¾ 21 0 m V Output voltage temperature V TC1 Ta = -30°C to +25°C ¾– 0.5 ¾ % characteristics 1 Output voltage temperature V TC2 Ta = 25°C to 85°C ¾– 0.5 ¾ % characteristics 2 Reference short-circuit current I RS ¾- 20 ¾ mA U.V.L.O. block Circuit operation start voltage V UON 2.8 3.1 3.4 V Hysteresis width V HYS 100 200 300 mV Error amplifier block Input offset voltage V IO -6 ¾ 6m V Input bias current I B -500 -25 ¾ nA Common-mode input voltage range V ICR - 0.1 ¾ 0.8 V High-level output voltage V EH V REF - 0.3 VREF - 0.1 ¾ V Low-level output voltage V EL ¾ 0.1 0.3 V Output sink current I SINK V FB = 0.8 V ¾ 8 ¾ mA Output source current I SOURCE V FB = 0.8 V ¾- 120 ¾m A Open-loop gain A V ¾ 70 ¾ dB Common-mode ripple rejection ratio CMRR ¾ 50 ¾ dB Output block Oscillation frequency f OUT R T = 15 kW , CT = 200 pF 175 195 215 kHz Maximum duty ratio Du max R T = 15 kW, C T = 200 pF 85 90 95 % Output saturation voltage V OL IO = 50 mA, RT = 15 kW¾ 0.9 1.2 V Output leak current I LEAK V CC = 34 V, ¾¾ 10 mA when output transistor is off RT terminal voltage V RT ¾ 0.5 ¾ V Maximum oscillation frequency f OUT(max) R T = 5.6 kW, C T = 150 pF ¾ 500 ¾ kHz Frequency supply voltage f dV fOUT = 200 kHz, ¾– 2 ¾ % characteristics V CC = 3.6 V to 34 V Frequency temperature characteristics 1fdT1 fOUT = 200 kHz, ¾– 3 ¾ % Ta = -30°C to +25°C Frequency temperature characteristics 2fdT2 fOUT = 200 kHz, ¾– 3 ¾ % Ta = 25°C to 85°C
AN8015SH Voltage Regulators n Terminal Equivalent Circuits Pin No. Equivalent circuit Description I/O
1 CT: O
The terminal used for connecting a timing capaci- tor to set oscillation frequency. Use a capacitance value within the range of 100 pF to 27 000 pF. Use a oscillation frequency in the range of 2 kHz to 500 kHz.
2 RT: I
The terminal used for connecting a timing resistor to set oscillation frequency. Use a resistance value within the range of 5.6 kW to 15 kW . The terminal voltage is 0.5 V typ. 3 S.C.P.: O The terminal used for connecting a capacitor to set the time constant of soft start and timer latch short- circuit protection circuit. Use a capacitance value in the range of more than 1 000 pF. The charge current is about 1.1 mA at R T = 15 kW ICHG = V RT [A]R T 30
4 GND: ¾
comp. To PWM input IO 210 V REF RT(V RT » 0.5 V) 100 W OSC PWM S.C.P. QS 1.83 VR V REF ICHG S.C.P. CT PWM Latch n Electrical Characteristics at VCC = 12 V, RT = 15 W , CT = 200 pF, Ta = 25°C (continued) Parameter Symbol Conditions Min Typ Max Unit Short-circuit protection circuit block Input threshold voltage V THPC 1.73 1.83 1.93 V Input standby voltage V STBY 1.15 1.25 1.35 V Input latch voltage V IN ¾ 30 120 mV Charge current I CHG V SCP = 0 V -1.32 -1.1 - 0.88 mA Comparator threshold voltage V THL ¾ 1.83 ¾ V Whole device Total consumption current I CC R T = 15 kW¾ 1.8 2.8 mA Total consumption current 2 I CC2 R T = 5.6 kW, C T = 150 pF ¾2 . 5 ¾ mA
Voltage Regulators AN8015SH Pin No. Equivalent circuit Description I/O
5 Out: O
Open-collector type (darlington) output terminal. The absolute maximum rating of output current is 100 mA Use with a steady-state output current under 50 mA. 6V CC : ¾ The terminal for applying supply voltage. Use with a operating supply voltage within the range of 3.6 V to 34 V. 7V REF :O The output terminal for the reference voltage (2.46 Use with a load current -3 mA or under. This terminal is incorporating the short-circuit protection circuit, and the short-circuit current is about -20 mA. Use the V REF for the reference input setting of the error amplifier. 8I N +:I The noninverted input terminal of the error ampli- fier. For common-mode input, use in the range of - 0.1 V to +0.8 V. 9I N -:I The inverted input terminal of the error amplifier. For common-mode input, use in the range of - 0.1 V to +0.8 V.
10 FB: O
The output terminal of the error amplifier. The source current is about -120 mA, and the sink current is about 8 mA. Correct the frequency characteristics of the gain and the phase by connecting a resistor and a ca- pacitor between this terminal and IN- terminal. n Terminal Equivalent Circuits (continued) V CC V REF overcurrent detection Bias to other block V REF V REF 120 mA CT PWM 8 mA V REF
AN8015SH Voltage Regulators n Application Notes [1] Main characteristics Reference voltage temperature characteristics Maximum duty ratio temperature characteristics Oscillation frequency temperature characteristics Timing capacitance ¾ Oscillation frequency Maximum duty ratio ¾ Oscillation frequency 2.45 -40 -20 100 Ambient temperature Ta (°C) Reference voltage VREF (V) 2.46 2.47 2.48 2.49 2.50 806040200 V CC = 12 V IREF = -1 mA 89.0 -40 -20 100 Ambient temperature Ta (°C) Maximum duty ratio Dumax (%) 89.5 90.0 90.5 91.0 806040200 V CC = 12 V C T = 200 pF R T = 15 kW 180 -40 -20 100 Ambient temperature Ta (°C) Oscillation frequency fOUT (kHz) 185 190 195 200 806040200 V CC = 12 V C T = 200 pF R T = 15 kW Oscillation frequency fOUT (Hz) 1 k 1 M 100 k 10 k 100 00010 0001 000100 Timing capacitance CT (pF) V CC = 12 V Ta = 25°C R T = 5.6 kW R T = 10 kW R T = 15 kW 10k 100k 1M Maximum duty ratio Dumax (%) 100 Oscillation frequency fOUT (Hz) V CC = 12 V Ta = 25°C R T = 5.6 kW R T = 15 kW 10k 100k 1M Triangular wave maximum amplitude voltage (V) 1.4 0.2 Oscillation frequency fOUT (Hz) 0.4 0.6 0.8 1.0 1.2 V CC = 12 V R T = 15 kW Ta = 25°C Oscillation frequency ¾ Triangular wave maximum amplitude voltage
Voltage Regulators AN8015SH n Application Notes (continued) [1] Main characteristics (continued) Supply voltage ¾ Reference voltage Supply voltage ¾ Total consumption current Reference voltage line regulation Total consumption current line regulation Timing resistance ¾ Total consumption current Timing resistance ¾ Output saturation voltage Supply voltage VCC (V) Reference voltage VREF (V) 0.5 1.0 1.5 2.0 2.5 3.0 1 2 3 4 Ta = 25°C IREF = -1 mA Supply voltage VCC (V) Total consumption current ICC (mA) 0.5 1.0 1.5 2.0 2.5 3.0 1 2 3 4 Ta = 25°C R T = 5.6 kW R T = 15 kW 2.42 05 3 5 Supply voltage VCC (V) Reference voltage VREF (V) 2.44 2.46 2.48 2.50 2.52 3025201510 Ta = 25°C IREF = -1 mA 1.5 05 3 5 Supply voltage VCC (V) Total consumption current ICC (mA) 2.0 2.5 3.0 3025201510 Ta = 25°C R T = 5.6 kW R T = 15 kW 1.0 42 0 Timing resistance RT (kW ) Total consumption current ICC (mA) 1.5 2.0 2.5 8 12 16 V CC = 12 V Ta = 25°C 0.80 42 0 Timing resistance RT (kW ) Output saturation voltage VOL (V) 0.81 0.82 0.83 0.84 0.85 8 12 16 V CC = 12 V Ta = 25°C IO = 50 mA
and used as the operating power supply for the IC inside. It is possible to take out a load current of up to -3 mA . V REF terminal is short circuited.
- Triangular wave oscillation block
The triangular wave is connected with the inverted input of PWM comparator of the IC inside. inputs the amplified signal to the PWM comparator. resistor and capacitor between the error amplifier output terminal (pin 10) and the inverted input terminal (pin 9). given in the following equations. Figure 3. Connection method of error amplifier
- R2 R1 + R2 V REF PWM comparator inputError amp. IN+ 8 IN- 9 FB 10V OUT R NF C NF 4. Timer latch short-circuit protection circuit This circuit protects the external main switching devices, flywheel diodes, and choke coils, etc. from destruction or deterioration if overload or short-circuit of power supply output lasts for a certain time. The timer latch short-circuit protection circuit detects the output level of the error amplifier. When the output voltage of DC-DC converter drops and the output level of error amplifiers exceeds 1.85 V, the low-level output is given and the timer circuit is actuated to start the charge of the external protection enable capacitor. If the output of the error amplifier does not return to a normal voltage range by the time when the voltage of this capacitor reaches 1.83 V, it sets the latch circuit, cuts off the output drive transistor, and sets the dead-time at 100%.
voltage is low in the transient state of power on/off. fall time of the power supply voltage, it has hysteresis width of 200 mV and operates 2.9 V or less. than any one of the following voltages : the voltage of the error amplifier output (pin 10) of the inverted input, S.C.P. terminal (pin 3), and the voltage for dead-time which is fixed inside the IC. according to the time constant determined by the capacitance of externally attached capacitor and the charge current. The maximum duty ratio is fixed at approximately 90% by the voltage for dead-time.
- Oscillation frequency setting method
the externally attached timing resistor RT . typical and 0.37 V typical respectively. The output frequency fOUT is equal to fOSC since it is PWM-controlled. Figure 4. Triangular wave oscillation waveform
within the recommended range shown in figure 5. frequency" for setting the timing capacitance. T and increase in the circuit current. FB with the reference voltage of 1.85 V at all the time.
- 1 [A]R T 30 V RT is approximately 0.5 V and ICHO becomes approximately 1.1 mA when RT = 15 kW . Oscillation frequency fOUT (Hz) 1 k 1 M 100 k 500 k 10 k 15 k5 k 5.6 k Timing resistance RT (W ) 10 k
Figure 5. Timing resistance recommended condition
output drive transistor by enabling the low input voltage malfunction prevention circuit, and sets the dead-time at 100%. approximately 30 mV but the latch circuit is not reset unless the power is turned off. Figure 6. Short-circuit protection circuit
Voltage Regulators AN8015SH 2. Chopper method inverting type 25.5 kW 4.5 kW 8.2 kW 0.1 mF 3.6 kW 120 kW 1 000 pF SBD V O 5 V V CC FB10CT 1 IN-9RT 2 IN+8S.C.P. 3 V REF7GND 4 V CC6Out 5 200 pF 0.1 mF15 kW 8.2 kW 0.1 mF 3.6 kW 120 kW 130 kW 1 000 pF SBD V O -24 V V CC 9.1 kW FB10CT 1 IN-9RT 2 IN+8S.C.P. 3 V REF7GND 4 V CC6Out 5 200 pF 0.1 mF15 kW n Application Circuit Examples 1. Chopper method step-down type
AN8015SH Voltage Regulators n Application Circuit Examples (contined) 3. On/off circuit example 1) Method to cut VCC line 2) Method to cut S.C.P. line 4. Using method Since the on/off circuit is not incorporated in this IC, it is required to add on/off circuit externally to provide a standby function. When the switch (Q1) is inserted between the VCC line and the Vcc pin of the IC (pin 6) as shown in 3. 1), the standby current is suppressed to 0. When the output is turned off by decreasing the S.C.P. terminal voltage below the lower limit of the triangular wave (0.37 V typical) as shown in 3. 2), the consumption current does not decrease because the IC is operating. 5. Usage notes The rise time of the V CC becomes sharp especially in the case of 3. 1). At that time, there is a case that the internal latch circuit of the IC is set so that the circuit fails to start. Adjust C7 or C8 so that the rise time for VREF pin (pin 7) becomes 10 ms or longer. ICC SBD V O V CC On/off FB10CT 1 IN-9RT 2 IN+8S.C.P. 3 V REF7GND 4 V CC6Out 5 Standby current » 0 mA C7 ICC SBD V O V CC On/off FB10CT 1 IN-9RT 2 IN+8S.C.P. 3 V REF7GND 4 V CC6Out 5 Consumption current when output off» 1.8 mA