AN8011S PANASONIC

Document overview

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Technical content

2-channel step-down, step-up, or inverting use DC-DC converter control IC n Overview The AN8011S is a DC-DC converter control IC with two-channel output using the PWM method which allows 500 kHz high-speed control. Respecitve output operation can be completely synchronized with each other by using the same oscillation output. n Features

  • PWM control frequency of 500 kHz is available.
  • Wide operating supply voltage range (VCC = 3.6 V to 34 V)
  • Built-in 2-channel of open collector type for out- put (A single-channel is also usable for inverted amplification type)
  • Each output can be stopped independently by the external control .
  • Built-in on/off function for the operation/stop of IC Incorporating circuit for short-circuit portection and under- voltage lock-out (U.V.L.O.)
  • The latch circuit is externally controllable.
  • Low consumption current (during operation: 5 mA, during standby: 2 µA) n Applications
  • LCD displays, digital still cameras, and PDAs n Block Diagram Unit: mm SOP016-P-0225A 0.3 (0° to 10°) (0.15) 10.1±0.3 4.2±0.3 6.5±0.3 16 9 1.27(0.605) Seating plane Seating plane 0.40±0.25 0.1±0.1 1.5±0.2 V REF V CC Out1 DTC1 FB1 IN-1 IN+ Latch U.V.L.O. OSC Latch On/ Off Unlatch pro. Unlatch pro. Short pro. Error amp. Error amp. PWM1 PWM2 V REF 1CT RT On/Off 4IN-2 FB2 5 6DTC2 7Out2 8GND

AN8011S Voltage Regulators n Pin Descriptions Pin No. Symbol Description

1 CT Pin for connecting the oscillation frequency setting capacitor for triangular oscillation

circuit. Frequecy of triangular oscillation is set by connecting a capacitor between this terminal and GND.

2 RT Resistor connection pin for setting the oscillation frequency of triangular oscillation

circuit. Frequecy of triangular oscillation is set by connecting resistance between the pin and GND 3 On/Off "On/Off" pin for turning on/off IC. "Low" stops IC (output off) and "High" operates IC. 4I N -2 Inverted input pin for channel 2 error amplifier 5 F/B 2 Output pin for channel 2 error amplifier. Gain setting or phase compensation is per- formed by connecting resistor or capacitor between the pin and IN-2. It is also connected to PWM short-circuit protecion. 6 DTC 2 Pin for setting dead-time period of channel 2. The dead-time of channel 2 is set by connecting external resistor. Soft start function can be also given by connecting capaci- tor in parallel with the external resistor. In addition, only channel 2 output can be turned off by decreasing the pin voltage to below 0.12 V. (short-circuit protection function stop circuit) 7 Out 2 Channel 2 open-collector type output pin. I O = 100 mA maximum 8 GND Grounding pin of signal system. 9V CC Power supply voltage application pin. It detects start voltage and stop voltages 10 Out 1 Channel 1 open-collector type output pin. I O = 100 mA maximum 11 DTC 1 Pin for setting dead-time period of channel 1. The dead-time period of channel 1 is set by connecting external resistor. Soft start function can be also given by connecting capacitor in parallel with the external resistor. In addition, only channel 1 output can be turned off by decreasing the pin voltage to below 0.12 V. (short-circuit protection function stop circuit) 12 F/B 1 Output pin for channel 1 error amplifier. Gain setting or phase compensation is per formed by connecting resistor or capacitor between the pin and IN-1. It is also con nected to PWM short-circuit protection. 13 IN -1 Inverted input pin for channel 1 error amplifier. 14 IN + Pin for noninverted input of channel 1error amplifier.

15 Latch Pin for connecting the time constant setting capacitor for timer latch type short-circuit

protection circuit. The time constant for short-circuit protection is set by connecting a capacitor between this terminal and GND. 16 V REF Internal reference voltage output pin (2.5 V(allowance: –3%)). If a load of 20 mA typical or more is applied, the overcurrent protection operates to reduce VREF and switching operation stops.

Voltage Regulators AN8011S n Recommended Operating Range Parameter Symbol Range Unit Supply voltage V CC 3.6 to 34 V Parameter Symbol Rating Unit Supply voltage V CC 35 V Power dissipation * PD 380 mW Operating ambient temperature T opr -30 to +85 °C Storage temperature T stg -40 to +125 °C n Absolute Maximum Ratings at Ta = 25°C Parameter Symbol Conditions Min Typ Max Unit Reference voltage block Output voltage V REF 2.413 2.5 2.588 V Input regulation with input fluctuation Line VCC = 3.6 V to 34 V ¾ 32 0 m V Load regulation Load I REF = 0 mA to 5 mA ¾ 21 0 m V Output voltage temperature V TC1 Ta = -25°C to + 25°C ¾– 1 ¾ % characteristics 1 * Output voltage temperature V TC2 Ta = 25°C to 85°C ¾– 1 ¾ % characteristics 2 * Overcurrent protection drive current * ICC 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 1 Input offset voltage 1 V IN-O1 -6 ¾ 6m V Input current 1 I B1 -500 -25 100 nA Common-mode input voltage range V CM 0.5 ¾ 0.8 V High-level output voltage 1 V EH1 V REF - 0.3 ¾¾ V Low-level output voltage 1 V EL1 ¾¾ 0.5 V Error amplifier block 2 Input current 2 I B2 25 ¾ 100 nA Common mode input threshold voltageV IN+ 0.72 0.75 0.78 V High-level output voltage 2 V EH2 V REF - 0.3 ¾¾ V Low-level output voltage 2 V EL2 ¾¾ 0.5 V n Electrical Characteristics at VCC = 12 V, Ta = 25°C Note) 1. Do not apply ecternal currents or voltages to any pins not speifically mentioned. For circuit currents, '+' denotes current flowing into the IC, and '-' denotes current flowing out of the IC. 2 *: When using the IC at Ta of 25°C or more, the power dessipation should be decreased 3.8 mW per 1°C.

AN8011S Voltage Regulators Parameter Symbol Conditions Min Typ Max Unit PWM comparator 1/2 block High-level input threshold voltage VDT-H fOSC = 200 kHz, duty = 100% 1.2 ¾¾ V Low-level input threshold voltage VDT-L fOSC = 200 kHz, duty = 100% ¾¾ 0.6 V Input current I DTC R T = 20 kW- 37 -34 -31 mA Output 1/2 block Output frequency 1 f OUT1 C T = 150 pF, RT = 20 kW , IO = 30 mA 180 200 220 kHz Frequency 1 f dv V CC = 3.6 V to 34 V -2 ¾ 2% C T = 150 pF, RT = 20 kW Output duty ratio 1 Du 1 CT = 150 pF, RT = 20 kW , RDTC = 24 kW 40 45 50 % Output duty ratio 2 Du 2 CT = 150 pF, RT = 20 kW , RDTC = 33 kW 65 75 85 % Output saturation voltage 1 V O(sat)1 IO = 30 mA ¾¾ 0.9 V Output saturation voltage 2 V O(sat)2 IO = 100 mA ¾¾ 1.2 V Output leak current 1 I OLe1 V CC = 34 V, when output ¾¾ 10 mA transistor is off Frequency temperature characteristics 1 * fdT1 fOSC = 200 kHz, Ta = -30°C to +25°C ¾– 9 ¾ % Frequency temperature characteristics 2 * fdT2 fOSC = 200 kHz, Ta = 25°C to 85°C ¾– 9 ¾ % Output frequency 2* fOUT2 C T = 150 pF, RT = 6.6 kW , IO = 30 mA ¾ 500 ¾ kHz Frequency 2* fdv2 V CC = 3.6V to 34V, ¾– 2 ¾ % C T = 150 pF, RT = 6.6 kW Short-circuit protection block Input threshold voltage V SLTH 1.75 1.85 1.95 V Latch drive voltage V SLON 1.15 1.25 1.35 V Charge current ICHG -120 -50 -40 mA Unlatch pro. 1/2 block Input threshold voltage V ULTH 0.12 ¾¾ V On/off block Threshold voltage V TH 0.8 ¾ 2V Whole device Total consumption current ICC V CC = 12 V, RT = 20 kW¾ 57 m A Total consumption current fluctuationICC(max.) V CC = 3.6 V to 34 V, RT = 20 kW¾ ¾ 2m A Standby consumption current I CC(SB) V CC = 12 V, VREF is down ¾¾ 2 mA Maximum standby consumption current ICC(SB-M) V CC = 34 V, VREF is down ¾¾ 5 mA n Electrical Characteristics(continued) at VCC = 12 V, Ta = 25°C Note) *: These characteristics are theoretical values based on the IC design and are not guaranteed.

Voltage Regulators AN8011S Pin No. Equivalent circuit Description I/O

1 CT: O

The terminal used for connecting a timing capacitor to set oscillator frequency. Use a capacitance value within the range of 100 pF to 0.1mF. For frequency setting method, re- fer to the "Application Notes, [2] Function descriptions" section. Use the oscillation fre- quency in the range of 1 kHz to 500 kHz.

2 RT: I

The terminal used for connecting a timing resistor to set oscillattion frequency. Use a resistance value ranging from 5.1 kW to 20 kW . The terminal voltage is 0.67 V typ.

3 On/Off: I

The terminal for on/off control. High-level input: normal operation ON/OFF > 2.0 V typ.) Low-level input: standby state (VON/OFF < 0.8 V typ.) The total current consumption in the standby state can be suppressed to a value below 5 mA. 4I N -2: I The terminal for the inverted input of ch.2 error amplifier. Use a common-mode input ranging from - 0.1 V to 0.8 V. n Terminal Equivalent Circuits OSC comp. To PWM input V REF CT IO 2IO OSC PWM RT (= 0.67 V) V REF 16 17 kW Internal circuit start/stop 13 kW On/Off 0.75 V IN-2 V REF 16

AN8011S Voltage Regulators Pin No. Equivalent circuit Description I/O

5 FB2: O

The output terminal of ch.2 error amplifier. Its source current is -25 mA typ. and sink current is 8 mA typ. Correct the frequency characteristics of the gain and the phase by connecting a resistor and a capacitor between the terminal and IN-2 terminal.

6 DTC2: I

1) Terminal for connecting a resistor and a capacitor for setting the dead-time and the soft start period of ch.2 PWM output. Input current I DTC is determined by the tim- ing resistor RT so that dispersion, and fluc- tuation with temperature are suppressed. The input current is -35 mA typ. when R T = 20 kW IDTC2 = VRT · 1.04 (A) RT (VRT : 0.67 V typ.) 2) The ch.2 output can be turned off by reduc- ing the terminal voltage to below 0.12 V. (short-circuit protection function stop)

7 Out2: O

The ch.2 open-collector type (Darlington) output terminal. The absolute maximum rating of ouput cur- rent is 150 mA. Use with an output current under 100 mA normally.

8 GND: ¾

9V CC : ¾ The pin to which supply voltage is applied. Use within an operating supply voltage range of 3.6 V to 34 V. n Terminal Equivalent Circuits (continued)

5 FB2

25 mA typ. 8 mA typ.

6 DTC2

U.V .L.O. output V REF 16 Out2

8 GND

Voltage Regulators AN8011S Pin No. Equivalent circuit Description I/O

10 Out1: O

The ch.1 open collector type (darlington) output terminal. The absolute maximum rating of output cur- rent is 150 mA. Use with an output current of 100 mA or less normally.

11 DTC1: I

1) Terminal for connecting a resistor and a capacitor for setting the dead-time and the soft start period of ch.1 PWM output. Input current I DTC is determined by the tim- ing resistor RT so that dispersion and fluctu- ation with temperature are suppressed. The input current is -35 mA typ, when R T = 20 kW . IDTC2 = VRT · 1.04 (A) RT (VRT : 0.67 V typ.) 2) The ch.1 output can be turned off by reduc- ing the terminal voltage to below 0.12 V. (short-circuit protection function stop)

12 FB1: O

The output terminal of ch.1 error amplifier. Its source current is -25 mA typ. and sink current is 8 mA typ. Correct the frequency characteristics of the gain and the phase by connecting a resistor and a capacitor between the terminal and IN-1 terminal.

13 IN -1: I

The terminal for the inverted input of ch.1 error amplifier. Use a common-mode input ranging from - 0.1 V to +0.8 V.

14 IN +:I

The terminal for noninverted input of ch.1 error amplifier. Use a common-mode input ranging from - 0.1 V to +0.8 V. n Terminal Equivalent Circuits (continued) V REF 16 Out1

11 DTC1

U.V .L.O. output

12 FB1

25 mA typ. 8 mA typ. IN + IN - 1 V REF

AN8011S Voltage Regulators Pin No. Equivalent circuit Description I/O

15 Latch: O

Terminal for connecting the time constant setting capacitor for timer latch short-circuit protection circuit. The charge current I CHG is about -80 mA.

16 V REF :O

The output terminal for the reference voltage (2.5 V typ.). Use it with a load current of -1 mA or under. The terminal has a built-in short-circuit pro- tection circuit, and the short-circuit current is -20 mA typ. Use the terminal for setting the reference in- put of the error amplifier. n Terminal Equivalent Circuits (continued) R S Q Latch15 1.25 V typ. 1.25 V typ. ICHG Latch V REF 16 4.2 kW typ. 10kW typ. 30 kW typ. V CC 9 V REF V REF overcurrent detection Bias to other blocks

Voltage Regulators AN8011S n Application Notes [1] Main characteristics Reference voltage temperature characteristics Maximum duty ratio temperature characteristics 2.480 2.485 2.490 2.495 2.500 -40 100 Ambient temperature Ta (°C) Reference voltage VREF (V) -20 0 20 40 60 80 -40 100 Ambient temperature Ta (°C) Maximum duty ratio Du(45) (%) -20 0 20 40 60 80 Output frequency temperature characteristics DTC pin voltage ¾ Output duty ratio 200 201 202 203 204 205 206 207 208 209 210 -40 100 Ambient temperature Ta (°C) Output frequency fOUT (kHz) -20 0 20 40 60 80 0 100 DTC pin voltage (V) Output duty ratio (%) 0.5 1 1.5 fOUT = 500 kW fOUT = 200 kW Output frequency characteristics 100 500 102 C T (pF) Output frequency fOUT (kHz) 103 104 105 R T = 10 kW R T = 5.1 kW R T = 20 kW

Voltage Regulators AN8011S n Application Notes (continued) [2] Function descriptions (continued) 4. Timer latch short-circuit protection circuit This circuit protects the external main swiching devices, switching diodes, choke coils, and etc. from destruction or deterioration if overload or short-circuit of power supply output lasts for a certain time. The timer latch type short-circuit protection circuit detects the output level of each error amplifier, and when the ouput level of either one or both of the error amplifiers exceeds 1.85 V typical, the timer circuit is actuated, and initiates charging the external capacitor for protection enable. If the ouput of the error amplifier does not return to a normal voltage range by the time when the voltage of this capacitor reaches 1.25 V, it sets the latch circuit, cuts off the ouput drive transistor, and sets the dead time to 100%. This circuit protects the system from destruction or deterioration due to control malfunction caused by the supply voltage reduction in the transient state of power on or off. The low input voltage malfunction prevention circuit detects the internal reference voltage according to the supply voltage level, and cuts off the output drive transistor by resetting the latch circuit, thereby setting the dead- time to 100% and keeping the latch terminal low. 6. PWM comparator block The PWM comparators, each has one inverted input, and two noninverted inputs, and controls the on-period of output pulse in accordance with the input voltage. It turns on the output transistor during the period when the triangular wave of C T terminal is lower than either the error amplifier ouput voltage or the DTC terminal voltage. The dead-time is set by the addition of a resistor between the DTC terminal and GND. By the addition of a capacitor in parallel with the external resistor RDTC , the soft start function which gradually extends the on-period of the ouput pulse by the RC time constant when the power supply is turned on starts to work. 7. Output block The ouput drive transistor is of open-collector type output connected in Darlington circuit of emitter common GND. The breakdown voltage of the collector ouput terminal is 34 V and it is possible to obtain up to 100 mA ouput current. 8. Remote circuit It is possible to switch on/off the IC control by an external control signal. When the on/off terminal voltage is lowered to a value below approximately 0.8 V, the internal reference voltage goes down, thereby the IC control is stopped and the circuit current is decreased to 5 mA or less. When the on/off terminal voltage is increased to a value higher than approximately 2.0 V, the internal reference voltage raises and the control operation is started. [3] The time constant setting method for timer latch type short-circuit protection circuit Figure 3 shows the block diagram of the protection latch circuit. The comparator for short-circuit protection compares the output voltage of error amplifier V FB with the reference voltage (1.85 V) at all the time. When the load conditions of DC-DC converter output is stabilized, there is no fluctuation of error amplifier output, and the short- circuit protection comparator also keeps the balance. At this moment, the switch SW1 will be in the off state, and the latch terminal voltage will be kept at approximately 0.9 V typical. When the load conditions suddenly change, and high-level signal (1.85 V typical of higher) is inputted from the error amplifier to the noninverted input of the short-circuit protection comparator, the short-circuit protection com- parator outputs the high-level signal. This signal turns on the switch SW1, and the charging to the capacitor C S connected externally to the latch terminal is started with a current of 80 mA typical. When the external capacitor CS is charged up to approximately 1.25 V typical, the latch circuit is set and the under- voltage lock-out circuit (U.V.L.O.) is enabled, thereby the ouput drive transistor is cut off and the dead-time is set to 100%. Once the under-voltage lock-out circuit (U.V.L.O.) is enabled, the latch circuit will not be reset unless the power supply is switched off.

capacitor so as to start up the DC-DC converter output voltage before setting the latch circuit in the later stage. Especially, pay attention to the delay of the start-up time when applying the soft-start. amplifier output terminal of the channel, to low by setting DTC terminal to 0.12 V or less through external signal. each channel in any required sequence. Figure 3. Short-circuit protection circuit

11 Unlatch protection

Figure 4. Unlatch protection circuit

Voltage Regulators AN8011S n Application Circuit Examples

  • Application circuit example 1 V REF Latch IN+ IN-1 FB1 DTC1 Out1 V CC f = 200 kHz Duty = 75% To pin 4 CT On/Off IN-2 FB2 DTC2 Out2 GND RT V CC -5 V 20 kW 14 kW 6 kW 33 kW 33 kW 150 pF 0.01 mF 0.01 mF 0.1 mF 0.1 mF 3 V 3 V

3 V 5 V

U.V .L.O. OSC Latch On/ Off Unlatch pro. Unlatch pro. Short pro. Error amp. Error amp. PWM1 PWM2 25.5 kW 120 kW 120 kW 4.5 kW 23 kW 7 kW 25.5 kW 4.5 kW

AN8011S Voltage Regulators n Application Circuit Examples

  • Application circuit example 2 V IN = 7 V 3.3 V V CC = 7 V V CC = 7 V R 0.75 V 25.5 kW 500 W 500 W 4.5 kW 5 V V REF Latch IN+ IN-1 FB1 DTC1 Out1 V CC CT On/Off IN-2 FB2 DTC2 Out2 GND RT 20 kW 33 kW 100 W 33 kW 100 W 150 pF 0.1 mF 0.1 mF V REF U.V .L.O. OSC Latch On/ Off Unlatch pro. Unlatch pro. Short pro. Error amp. Error amp. PWM1 PWM2 2.5 V 0.01 mF 10 mF 120 kW 0.01 mF 120 kW