GL494 GL494 PWM CONTROL CIRCUIT Pin Configuration Description The GL494 incorporates on a single monolithic chip all the functions required in the construction of a pulse-widthmodulation control circuit. Designed primarily for power supply control, the GL494 contains an on-chip 5-volt regulator, two error amplifiers, adjustable oscillator, deadtime control comparator, pulse-steering flip-flop, and output-control circuitry. The uncommitted output transistors pro-vide either common-emitter or emitterfollower output capability. Push-pull or single-ended output operation may be selected through the outputcontrol function. The ar-chitecture of the GL494 prohibits the possibility of either output being pulsed twice during push-pull operation. NONINV INPUT 1 16 NON INV INPUT INV. INPUT 2 15 INV. INPUT FEEDBACK 3 14 REF. OUT 4 13 OUTPUT CONTROL Cr 5 12 Vcc Rr 6 11 C2 GND 7 10 E2 C1 8 9 E1 DEAD TIME CONTROL Features — Complete PWM Power Control Circuitry — Uncommitted Outputs for 200mA Sink or Source — Output Control Selects Single-Ended or Push-Pull Operation — Internal Circuitry Prohibits Double Pulse at Either Output — Internal Regulator Provides a Stable 5V Reference Supply — Variable Dead-Time Provides Control Over Total Range Function Table Output Control Output Function Grounded Single-ended or Parallel Output At Vref Normal Push-Pull Operation Block Diagram RT CT OUTPUT CONTROL OSCILLATOR (See Function Table) DEAD TIME CONTROL PULSE STEERING FLIP FLOP Q 0.1V T (4) ERROR AMPLIFIERS NONINVERTING(1) + INPUT INVERTING INPUT (2) INVERTING INPUT FEEDBACK Q PWM COMPARATOR (15) E1(9) C1(8) − ERROR AMP1 NONINVERTING(16) INPUT (13) + − VCC (12) REFERENCE REGULATOR ERROR AMP2 REF OUT (14) GND (7) (3) 1 E1(10) C2(11) GL494 Absolute Maximum Ratings Supply Voltage, VCC ……………………………………………………………………….. 41 Amplifier Input Voltage ……………………………………………………………….. VCC +0.3 Collector Output Voltage ……………………………………………………………………… 41 Continuous Total dissipation at (or below) 25 °C ………………………………………. 1000 Operating Free-Air Temperature Range ……………………………………………… -20 to 85 Storage Temperature Range ……………………………………………………….….. -65 to 150 Collector Output Current ………………………………………………………………….. 250 V V V mW °C °C mA Recommended Operation Conditions PARAMETER MIN MAX UNIT Supply Voltage, VCC 7 40 V Amplifier Input Voltage, V1 -0.3 VCC -2 V Collector Output Voltage, Vo 40 V Collector Output Current (Each Transistor) 200 mA Current Into Feed back Terminal 0.3 mA Timing Capacitor, C T 0.47 10,000 nF Timing Resistor, R T 1.8 500 KΩ Oscillator Frequency 1 300 KHz °C Operating Free-Air Temperature -20 85 Electrical Characteristics (Temperature −20 ~ 85°C , VCC =15V, f=10KHz) Reference Section PARAMETER TEST CONDITIONS MIN TYP(1) MAX UNIT 4.75 5 5.25 V Output voltage ( Vref ) IO = 1mA Input regulation VCC = 7 V to 40V, TA = 25°C 2 25 mV Output regulation IO = 1 to 10mA, TA = 25°C 1 15 mV Output Voltage change with temperature TA = −20°C to 85°C 0.2 1 % Short-circuit Output current(2) Vref = 0 35 mA Oscillator Section PARAMETER TEST CONDITIONS MIN TYP(1) MAX UNIT Frequency C T = 0.01µF , R T = 12 kΩ 10 KHz Standard deviation of frequency (3) All values of VCC , C T , R T , TA Constant 10 % Frequency change with Voltage VCC = 7 V to 40V, TA = 25°C 0.1 % Frequency change with temperature C T = 0.01µF , R T = 12 kΩ TA = −20°C to 85°C 2 2 % GL494 Dead Time Control Section PARAMETER TEST CONDITIONS Input bias current (pin 4) VI=0 to 5.25V Maximum duty cycle, Each output VI ( pin 4) =0V Input threshold voltage (pin 4) MIN TYP(1) MAX UNIT -2 -10 µA 45 Zero duty cycle % 3 Maximum duty cycle 3.3 0 V V Error Amp Sections PARAMETER TEST CONDITIONS MIN TYP(1) MAX UNIT Input offset voltage VO( PIN3) = 2.5V 2 10 mV Input offset current VO( PIN3) = 2.5V 25 250 nA Input bias current VO( PIN3) = 2.5V 0.2 1 µA Common-mode input voltage range VCC = 7V to 40V Open-loop voltage Amplification ∆VO = 3V, VO = 0.5 to3. 5V LOW -0.3 HIGH VCC − 2 70 Unity-gain bandwidth V 95 dB 800 KHz Common-mode rejection ratio VCC = 40V , TA = 25°C 65 80 dB Output sink current (pin 3) VID = −15mV to –5V, VO( pin 3) = 0.7V 0.3 0.7 mA Output source current (pin 3) VID = 15mV to 5V, VO( pin 3) = 3.5V -2 mA PWM Comparaor Section PARAMETER TEST CONDITIONS MIN TYP(1) MAX UNIT 4 4.5 V Input threshold voltage (pin 3) Zero duty cycle Input sink current (pin 3) VO( pin 3) = 0.7V 0.3 0.7 TEST CONDITIONS MIN TYP(1) MAX UNIT Common-emitter configuration, See Test Circuit 3 100 200 ns 25 100 ns Emitter-follower configuration, See Test Circuit 4 100 200 ns 40 100 ns mA Switching Characteristics PARAMETER Output Voltage rise time Output Voltage fall time Output Voltage rise time Output Voltage fall time 3 GL494 Output Section PARAMETER TEST CONDITIONS Collector off-state current VCE = 40V, VCC = 40V Emitter off-state current VCC = VC = 40V, VE = 0 MIN TYP(1) MAX UNIT 2 100 mA -100 mA Collector-emitter Common-emitter Saturation voltage Emitter-follower VE = 0, I C = 200mA 1.1 1.3 VC = 15V, I E = −200mA 1.5 2.5 Output control input current VI = Vref V 3.5 mA TYP(1) MAX UNIT VCC = 15V 6 10 mA VCC = 40V 9 15 mA Total Device PARAMETER Standby supply current Average supply current TEST CONDITIONS All other inputs & Outputs open V( pin 4) = 2V See Test circuit 1 MIN 7.5 Notes: (1) All typical values except for temperature coefficients are at TA = 25 °C (2) Duration of the short circuit should not exceed one second. (3) Standard deviation is a measure of the statistical distribution about the mean as derived from the formula N σ= ∑ (X n − X ) 2 n =1 N −1 4 mA GL494 Parameter Measurement Information 1.Dead time and Feedback Control Vcc=15V TEST INPUTS 0 Vcc VOLTAGE AT C2 OUTPUT 1 DEAD TIME (4) (8) C1 (9) E1 12kΩ FEEDBACK (3) Re (6) Cr (5) (11) C2 0.01µF (+) (16) ERROR (12) E2 (-) (15) AMP (+) (1) ERROR (-) (2) AMP (14) REF OUTPUT 50kΩ CONTROL GND (7) OUT Vcc VOLTAGE AT C1 150Ω 150Ω 2W 2W 0 OUTPUT 2 VOLTAGE AT CT THRESHOLD VOLTAGE DEAD-TIME CONTROL INTPUT (13) FEEDBACK 0V THRESHOLD VOLTAGE 0.7V MAX 0% DUTY CYCLE TEST CIRCUIT MAX VOLTAGE WAVEFORMS 2. Error Amplifier Characteristics + ERROR AMPLIFIER UNDER TEST FEEDBACK TERMINAL V1 – + VREF – OTHER ERROR AMPLIFIER 3. Common-Emitter Configuration 15V (EACH OUTPUT CIRCUIT) 68Ω 2W 90% 90% OUTPUT CL=15pF (INCLUDES PROBE AND JIG CAPACITANCE) 10% tr TEST CIRCUIT 10% tf OUTPUT VOLTAGE WAVEFORM 5 0% GL494 4. Emitter-Follower Configuration (EACH OUTPUT EIRCUIT) 15V 90% 90% 10% 10% OUTPUT 68Ω 2W tr tf CL=15pF (INCLUDES PROBE AND JIG CAPACITANCE) TEST CIRCUIT OUTPUT VOLTAGE WAVEFORM Typical Performance Curves FIGURE 1 – OSCILLATOR FREQUENCY versus TIMING RESISTANCE 100k 0.001 µF 10k AVOL, OPEN-LOOP VOATAGE GAIN (db) 300k Vcc=15V CT=0.01 µF 1k 0.1 µF 100 0.1 µF 30 1k 2k 5k 10k 20k 50k FIGURE 2 – OPEN LOOP VOLTAGE GAIN AND PHASE versus FREQUENCY 20 100 100k 200k 500k 1M 90 0 70 AVOL 60 ACH OUTPUT %DT. PERCENT DEADTIME, EACH OUTPUT 10 9 7 CT=0.01 µF 6 -40 -80 40 -100 30 -120 20 -140 10 -160 0 1.0 10 100 1k 10k 100k -80 1M f, FREQUENCY (Hz) FIGURE 3 – PERCENT DEAD TIME versus OSCILLATOR FREQUENCY Vcc=15V Voc=Vref V(PIN4)=0V -20 -60 θ 50 RT, TIMING RESISTANCE (Ω) 8 Vcc=15V Vo=3V RL=2kΩ 80 FIGURE 4 – PERCENT DUTY CYCLE versus DEAD-TIME CONTROL VOLTAGE 50 Vcc=15V Voc=Vref 1) CT=0.01 RT=10k 2) CT=0.001 RT=30K 40 30 1 5 20 4 2 3 0.01 µF 2 10 1 0 0 100 1k 10k 100k 0 fo, OSCILLATOR FREQUENCY (Hz) 1.0 2.0 DEAD TIME CONTROL VOLTAGE (V) 6 3.0 3.5 GL494 1.9 FIGURE 5 – EMITTER-FOLLOWER CONFIGURATION OUTPUT-SATURATION VOLTAGE versus EMITTER CURRENT 1.3 1.2 Vcc=15V 1.7 VCE(SAT), SATURATION VOLTAGE (V) VCE(SAT), SATURATION VOLTAGE (V) 1.8 1.6 1.5 1.4 1.3 1.2 1.1 0 50 100 150 200 250 IE, EMITTER CURRENT (mA) FUGURE 7 – STANDBY-SUPPLY CURRENT versus SUPPLY VOLTAGE 8.0 Icc, SUPPLY CURRENT (mA) FIGURE 6 – COMMON-EMITTER CONFIGURATION OUTPUT-SATURATION VOLTAGE versus COLLECTOR CURRENT 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0 0 5.0 10 15 20 25 30 35 40 Vcc, SUPPLY VOLTAGE (V) 7 Vcc=15V 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0 50 100 150 200 Ic, COLLECTOR CURRENT (mA) 250