AN8013SH PANASONIC
Document overview
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Technical content
Single-channel step-up or step-down DC-DC converter control IC n Overview The AN8013SH is a single-channel PWM DC-DC converter control IC. This IC implements DC-DC con- verters that provide a single arbitrary output voltage that is either a stepped-up or stepped-down level. It features a wide operating supply voltage range, low power, and a built-in overcurrent protection circuit to protect the switching transistor from damage or destruction. The AN8013SH is provided in a 0.5 mm pitch 10-pin surface mounting package and is optimal for use in miniature high-efficiency portable power supplies. n Features
- Wide operating supply voltage range (3.6 V to 34 V)
- Small consumption current (2.4 mA typical)
- Supports control over a wide output frequency range: 20 kHz to 500 kHz.
- Built-in pulse-by-pulse overcurrent protection circuit (Detection voltage: VCC - 100 mV)
- Built-in timer latch short-circuit protection circuit (charge current 1.3 mA typical)
- Incorporating the under-voltage lock-out (U.V.L.O.) circuit
- Built-in reference voltage circuit (Error amplifier reference input: 0.75 V (allowance: –4%))
- Output block is open-collector (darlington) type.
- High absolute maximum rating of output current (100 mA)
- Duty ratio with small sample-to-sample variations (55% – 5%).
- Adopts a 0.5-mm lead pitch 10-pin small outline package n Applications
- Switching mode power supply units (in portable equipment and other applications) 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 n Pin Descriptions CLM RT CT S.C.P. DTC V CC Out GND IN- FB
AN8013SH Voltage Regulators n Absolute Maximum Ratings at Ta = 25°C Parameter Symbol Rating Unit Supply voltage V CC 35 V CLM pin allowable application voltage VCLM 35 V Error amplifier allowable input voltage VIN- -0.3 to +2.5 V DTC pin allowable input voltage V DTC 2.5 V Out pin allowable application voltage VOUT 35 V Collector output current I OUT 100 mA Power dissipation (Ta = 85°C) P D 154 mW Operating ambient temperature T opr -30 to +85 °C Storage temperature T stg -55 to +150 °C n Recommended Operating Range at Ta = 25°C Parameter Symbol Min Max Unit Supply voltage rise time (0 to 3.6 V) t r (VCC )1 0 ¾m s Collector output voltage V OUT ¾ 34 V Collector output current I OUT ¾ 50 mA Timing capacitance C T 100 1 800 pF Timing resistance R T 5.1 15 k W Oscillator frequency f OUT 20 500 kHz Short-circuit protection time constant setting CSCP 1 000 ¾ pF capacitor n Block Diagram IN- FB 1.90 V S R Latch S R Latch V REF OSC V CC R S Q U.V.L.O. V REF V REFR T V REF R T 0.75 V 0.75 V 0.1 V S.C.P. CLM DTC5 CT3 RT2 PWM GND Out
Voltage Regulators AN8013SH n Electrical Characteristics at Ta = 25°C Parameter Symbol Conditions Min Typ Max Unit 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 threshold voltage V TH Voltage follower 0.72 0.75 0.78 mV Line regulation with input fluctuation Vdv Voltage follower, ¾ 28 m V V CC = 3.6 V to 34 V Input bias current I B -500 -25 ¾ nA High-level output voltage V EH 2.0 ¾¾ V Low-level output voltage V EL ¾¾ 0.3 V Input threshold voltage temperature Vdt1 Voltage follower, ¾– 1 ¾ % characteristics 1 Ta = -30°C to +25°C Input threshold voltage temperature Vdt2 Voltage follower, ¾– 1 ¾ % characteristics 2 Ta = -25°C to +85°C Output sink current I SINK V FB = 0.9 V ¾ 8 ¾ mA Output source current I SOURCE V FB = 0.9 V ¾- 120 ¾m A Open-loop gain A V ¾ 70 ¾ dB PWM Comparator Block Input threshold voltage: high V DT-H Duty: 100% 1.2 ¾¾ V Input threshold voltage: low V DT-L Duty: 0% ¾¾ 0.6 V Input current I DTC -12 -11 -10 A Output block Oscillation frequency f OUT R T = 15 kW , CT = 150 pF 185 205 225 kHz Output duty Du R DTC = 91 kW 50 55 60 % 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, when output Tr is off¾¾ 10 mA RT pin voltage V RT ¾ 0.59 ¾ V Maximum oscillation frequency f OUT(max) R T = 5.1 kW, C T = 120 pF ¾ 500 ¾ kHz Frequency supply voltage f dV fOUT = 200 kHz, ¾– 1 ¾ % characteristics V CC = 3.6 V to 34 V Frequency temperature f dT1 fOUT = 200 kHz, ¾– 3 ¾ % characteristics 1 Ta = -30°C to +25°C Frequency temperature f dT2 fOUT = 200 kHz, ¾– 3 ¾ % characteristics 2 Ta = 25°C to 85°C Note) At VCC = 12 V, RT = 15 kW , CT = 15 pF, unless otherwise specified.
AN8013SH Voltage Regulators n Electrical Characteristics at Ta = 25°C (continued) Parameter Symbol Conditions Min Typ Max Unit Short-circuit protection circuit block Input threshold voltage V THPC 0.70 0.75 0.80 V Input standby voltage V STBY ¾¾ 120 V Input latch voltage V IN ¾¾ 120 mV Charge current I CHG V SCP = 0 V -1.6 -1.3 - 1.0 mA Comparator threshold voltage V THL ¾ 1.90 ¾ V Overcurrent Protection Block Input threshold voltage V CLM V CC - 120 VCC - 100 VCC - 80 mV Delay time t DLY ¾ 200 ¾ ns Whole device Total consumption current 1 I CC R T = 15 kW¾ 2.4 3.5 mA Total consumption current 2 I CC2 R T = 5.1 kW, C T = 150 pF ¾3 . 4¾ mA Note) At VCC = 12 V, RT = 15 kW , CT = 15 pF, unless otherwise specified. n Terminal Equivalent Circuits Pin No. Pin I/O Function Internal equivalent circuit
1 CLM I Detects the overcurrent state in switching
transistor. Insert a resistor with a low resistance between this pin and VCC to detect overcurrent states. When this pin falls to a level 100 mV or more lower than V CC , the PWM output is turned off for that period thus narrowing the width of the on period. (This implements a pulse-by-pulse overcurrent protection technique.)
2 RT I Connection for the timing resistor that deter-
mines the oscillator frequency. Use a resistor in the range 5.1 kW to 15 kW . Thus the pin voltage will be about 0.59 V.
3 CT O Connection for the timing capacitor that
determines the oscillator frequency. Use a capacitor in the range 100 to 1 800 pF. See the "Application Notes, [2] and [3]" sections later in this document for details on setting the frequency. Use an oscillator frequency in the range 20 kHz to 500 kHz. V CC CLM comp. 50 mA50 mA 0.1 V S.C.P. 100 W RT (V » 0.59 V) OSC PWM V REF DTC IO 2IO OSC comp. V REF To PWM input
Voltage Regulators AN8013SH n Terminal Equivalent Circuits (continued) Pin No. Pin I/O Function Internal equivalent circuit 4 S.C.P. O Connection for the capacitor that determines the time constant for soft start and the timer latch short-circuit protection circuit. Use a capacitor with a value of 1 000 pF or higher. The charge current I CHG is determined by the timing resistor RT, and sample-to-sample and temperature variations can be suppressed. When R T is 15 kW , the current will be about -1.3 mA. ICHG = V RT
- 1 [A]R T 30
5 DTC I Connection for the resistor and capacitor that
determine the PWM output dead-time and the soft start period. The input current IDTC is determined by the timing resistor RT, and sample-to-sample and temperature variations can be suppressed. When R T is 15 kW , the current will be about -11 mA. ICHG = V RT
- 1 [A]R T 3.6
6 FB O Error amplifier output
A source current is about -120 mA and a sink current is about 8 mA. Correct the gain and the phase frequency characteristics by inserting a resistor and a capacitor between this pin and IN-pin. 7I N - I Error amplifier inverting input For common-mode input, use in the range - 0.1 V to +0.8 V.
8 GND ¾ Ground
S R Q Latch 0.75 V V REF ICHG U.V.L.O. PWMCT U.V.L.O. V REF IDTC PWMC T 120 mA 8 mA V REF V REF 0.75 V
AN8013SH Voltage Regulators Oscillator frequency temperature characteristics Timing capacitance ¾ Oscillator frequency n Terminal Equivalent Circuits (continued) Pin No. Pin I/O Function Internal equivalent circuit
9 Out O Open-collector (darlington) output
The absolute maximum rating for the output current is 100 mA. Use with a constant output current under 50 mA.
10 V CC ¾ Power supply connection
Provide the operating supply voltage in the range 3.6 V to 34 V. V REF n Application Notes [1] Main characteristics Maximum duty ratio temperature characteristics Error amplifier input threshold voltage temperature characteristics 0.750 0.758 0.760 -40 -20 0 20 40 60 80 100 Ambient temperature Ta (°C) Input threshold voltage VTH (V) 0.756 0.754 0.752 V CC = 12 V Voltage follower 195 210 215 -40 -20 0 20 40 60 80 100 Ambient temperature Ta (°C) Oscillator frequency fOUT (kHz) 205 200 V CC = 12 V C T = 200 pF R T = 15 kW 10k 100 1 000 10 000 Timing capacitance CT (pF) Oscillator frequency fOUT (Hz) 100k V CC = 12 V Ta = 25°C R T = 5.1 kW R T = 15 kW -40 -20 0 20 40 60 80 100 Ambient temperature Ta (°C) Maximum duty ratio Dumax (%) V CC = 12 V C T = 200 pF R T = 15 kW
Voltage Regulators AN8013SH n Application Notes (continued) [1] Main characteristics (continued) Input threshold voltage line regulation Total consumption current line regulation Timing resistance ¾ Total consumption current Timing resistance ¾ Output saturation voltage 0.745 0.760 0.765 0 5 10 15 20 25 30 35 Supply voltage VCC (V) Input threshold voltage VTH (V) 0.755 0.750 Ta = 25°C 2.0 3.5 4.0 0 5 10 15 20 25 30 35 Supply voltage VCC (V) Total consumption current ICC (mA) 3.0 2.5 Ta = 25°C R T = 5.1 kW R T = 15 kW 2.0 3.0 3.5 4 20 Timing resistance RT (kW ) Total consumption current ICC (mA) V CC = 12 V Ta = 25°C 2.5 8 12 16 4 20 Timing resistance RT (kW ) Output saturation voltage VOL (V) V CC = 12 V IO = 50 mA Ta = 25°C 8 12 16 0.80 0.84 0.85 0.83 0.82 0.81
power supply for the IC itself.
- Triangular wave generator
inverting input pin (pin 7).
- Timer latch short-circuit protection circuit
longer than a certain fixed period. timer circuit starts. This starts charging the external protection circuit delay time capacitor. the latch circuit latches, the output drive transistors are turned off, and the dead-time is set to 100%. power supply voltage falls during power on or power off. Figure 1. Connection method of error amplifier
amplifier output (pin 6) and the DTC pin (pin 5) voltage. The dead-time is set by adding a resistor between the DTC pin and ground.
- Overcurrent protection block
switching device (a bipolar transistor). to obtain up to 100 mA output current. Figure 2. Pulse-by-pulse overcurrent protection operating waveforms
- Setting the oscillator frequency
externally attached timing resistor RT . 0.35 V typical respectively. The output frequency fOUT is equal to fOSC since it is PWM-controlled. constant output current of 100 mA at the open-collector output, it is necessary to set RT value to 15 kW or smaller. frequency relationship in the "Application Notes, [1] Main characteristics" section of this document. (VCTL ) values depends on the oscillator frequency. Figure 3. Triangular wave oscillation waveform
Figure 4. Setting the dead-time
- 100 [%]
- 100 [%] V DTC = IDTC · RDTC n Application Notes (continued) [4] Setting the dead-time (maximum duty) (continued) Adding the external resistor RDTC and the capacitor CDTC in parallel implements a soft start function that causes the output pulse on width to increase gradually when the power supply is started. Use of this function can prevent DC-DC converter output overshoot. [5] Setting the time constant of the timer latch short-circuit protection circuit The structural block diagram of protection latch circuit is shown in figure 5. The comparator for short-circuit protection compares the output of error amplifier V FB with the reference voltage of 1.90 V all the time. When the load conditions of DC-DC converter output are stabilized, there is no fluctuation of error amplifier output, and the short-circuit protection comparator also keeps the balance. At this moment, the output transistor Q1 is in the conductive state and the S.C.P. pin is hold to about 30 mV through the clamp circuit. When the load conditions suddenly change, and high-level signal (1.90 V or higher) is input from the error amplifier to the non-inverted input of the short-circuit protection comparator, the short-circuit protection comparator outputs the low-level signal. Since this signal cuts off the output transistor Q1, the S.C.P. pin voltage V PE is released, and the externally connected capacitor CS starts charging according to the following equation : When the external capacitor CS has been charged up to about 0.75 V, it sets the latch circuit, cuts off the output drive transistor by enabling the low input voltage malfunction prevention circuit, and sets the dead-time at 100%. V PE = VSTBY + ICHG · tPE [V]C S 0.75 V = 0.03 V + ICHG · tPE C S C S = ICHG · tPE [F]0.72
- 1 [A]R T 30 V RT is about 0.5 V and ICHO becomes about 1.1 mA at RT = 15 kW . Once the low input voltage malfunction prevention circuit is enabled, the S.C.P. pin voltage is discharged to about 30 mV but the latch circuit is not reset unless the power is turned off. IN- FB 1.90 V
Figure 5. Short-circuit protection circuit special care is required to assure that the start time does not become excessive.
AN8013SH Voltage Regulators n Application Circuit Examples 1. Step-down circuit 2. Step-up circuit FB IN- GND Out V CC10 DTC CT RT CLM 15 kW 0.01 mF S.C.P. 150 pF In 62 kW 11 kW 100 kW 0.001mF Out +5 V 0.033 mF 110 kW f = 200 kHz Du max = 80% R DTC = 110 kW SBD 5FB IN- GND Out V CC10 DTC CT RT CLM 15 kW 0.01 mF S.C.P. 150 pF In 150 kW 10 kW 100 kW 0.001 mF Out +12 V 0.033 mF 110 kW f = 200 kHz Du max = 80% R DTC = 110 kW SBD
Voltage Regulators AN8013SH n Application Circuit Examples (continued) 3. On/off circuit example 1) Cutting the power supply line 2) Cutting the IC VCC line 4. Usage Since this IC does not include an on/off circuit, an external circuit must be added to implement a standby function. If a switch (Q1) is inserted in the power supply line as shown in on/off circuit example 1, the standby current can be held to 0. In this circuit, a transistor essentially equivalent to the one used for the main switching device (Q3) is required. If a switch (Q1) is inserted between the power supply line and the IC V CC pin (pin 10) as shown in on/off circuit example 2, the size of the switching device (Q1) can be reduced. However, the sample-to-sample variations in the Q1 saturation voltage will result in sample-to-sample variations in the overcurrent protection threshold level. 5. Usage Notes If an external on/off circuit is added, the V CC rise time may become excessively steep and the IC internal latch circuit may be set at that time, causing problems at power supply startup. To avoid such problems, set the value of C10 so that the V CC (pin 10) rise time is at least 10 ms. V O Standby current » 0 mA On/off In Q1 C10 FB IN- GND Out V CC ICC CT RT CLM S.C.P. SBD DTC V O On/off In C10 FB IN- GND Out V CC ICC CT RT CLM S.C.P. SBD 5DTC 5 Standby current » 0 mA