Pulse-Width-Modulation Control Circuits TL494 FEATURES SOP16/DIP16 (TOP VIEW) ● Complete PWM Power Control Circuitry ● Uncommitted Outputs for 200 mA Sink or Source Current NONINV INPUT 1 16 INV INPUT 2 15 INV INPUT 3 14 REF OUT CONTROL 4 13 OUTPUT CONTROL ● Circuit Architecture Allows Easy Synchronization CT 5 12 Vcc ● Moisture Sensitivity Level 3 RT 6 11 C2 GND 7 10 E2 C1 8 9 E1 ● Output Control Selects Single-Ended or Push-Pull Operation ● Internal Circuitry Prohibits Double Pulse at Either Output Error AMP 1 FEEDBAC K DEAD-TIME ● Variable Dead-Time Provides Control over Total Range ● Internal Regulator Provides a Stable 5-V Reference Supply,5% NONINV INPUT Error AMP 2 DESCRIPTION The TL494 incorporate on a single monolithic chip all the functions required in the construction of a pulse-width-modulation control, these devices offer the systems engineer the flexibility to tailor ORDERING INFORMATION the power supply control circuitry to his application. Device Package The TL494 contains an error amplifier, an on-chip adjustable TL494D 16 SOP oscillator, a dead-time control comparator, pulse-steering control TL494N 16 DIP flip-flop, a 5-volt, 5% precision regulator, and output-control circuit. The error amplifier exhibits a common-mode voltage range from -0.3 volts to Vcc -2 volts. The dead-time control comparator has a fixed offset that provides approximately 5% dead time when externally altered. The on-chip oscillator may be bypassed by terminating R T (pin 6) to the reference output and providing a sawtooth in put to CT (pin 5), or it may be used to drive the common circuits in synchronous multiple-rail power supplies. The uncommited output transistors provide either common-emitter or emitter-follower output capability. Each Device provides for push-pull or single-ended output operation, which may be selected through the output-control funct -ion. The architecture of these devices prohibits the possibility of either output being pulsed twice during push -pull operation. Functional Block Diagram OUTPUT CONTROL RT OSCILLATOR CT Q1 C1 DEAD E1 DEAD-TIME CONTROL COMPARATOR 0.1V C1 TIME CONTROL Q2 C2 E2 PULSE-STEERING FLIP-FLOP PWM COMPARATOR ERROR AMPLIFIER + NONINVERTING INPUT 1 - INVERTING INPUT Vcc ERROR AMPLIFIER NONINVERTING INPUT REFERENCE + 2 INVERTING INPUT Vref FEEDBACK - GND HTC 2008 - Ver. 1.2 1/6 Pulse-Width-Modulation Control Circuits TL494 Parameter measurement information Vcc = 15V Vcc 150 Ω 2W DEAD-TIME TEST INPUTS C1 FEEDBACK E1 RT C2 CT E2 150 Ω 2W OUTPUT 1 OUTPUT 2 12KΩ 0.01uF (+) (-) ERROR (+) (-) 50KΩ OUTPUT CONTROL REF OUT GND TEST CIRCUIT Vcc VOLTAGE AT C1 0 Vcc VOLTAGE AT C2 0 VOLTAGE AT CT DEAD-TIME CONTROL INPUT THRESHOLD VOLTAGE 0V THRESHOLD VOLTAGE FEEDBACK DUTY CIRCLE 0% 0.7 V 0% MAX FIGURE 1. OPERATIONAL TEST CIRCUIT AND WAVEFORMS HTC 2008 - Ver. 1.2 2/6 Pulse-Width-Modulation Control Circuits TL494 AMPLIFIER UNDER TEST + FEEDBACK TERMINAL - + Vref - OTHER AMPLIFIER FIGURE 2. AMPLIFIER CHARACTERISTICS 15 V (EACH OUTPUT CIRCUIT) 68 Ω 2W t OUTPUT f CL=15pF (Includes probe and jig capacitance) 90% r t f 90% 10% TEST CIRCUIT t 10% OUTPUT VOLTAGE WAVEFORM FIGURE 3. COMMON-EMITTER CONFIGURATION 15 V (EACH OUTPUT CIRCUIT) 90% 10% 90% 10% 68 Ω 2W t CL=15pF (Includes probe and jig capacitance) TEST CIRCUIT r OUTPUT VOLTAGE WAVEFORM FIGURE 4. EMITTER-FOLLOWER CONFIGURATION HTC 2008 - Ver. 1.2 3/6 Pulse-Width-Modulation Control Circuits TL494 ABSOLUTE MAXIMUM RATINGS OVER OPERATING FREE-AIR TEMPERATURE RANGE Rating Unit Value Supply voltage, Vcc 41 Amplifier input voltage V Vcc +0.3 Collector output voltage 41 Collector output current 250 mA Operating free-air temperature range -40 to 125 Storage temperature range -65 to 150 Lead temperature 1,6 mm from case for 10 seconds o C 260 RECOMMENDED OPERATING CONDITIONS Value Parameter MIN Supply voltage, Vcc Amplifier input voltage, Vi Unit MAX 7 40 -0.3 Vcc -2 V Collector output voltage, Vo 40 Collector output current (each transistor) 200 Current into feedback terminal Timing capacitor, C T 0.3 0.47 10000 nF Timing resistor, R T 1.8 500 1 300 KΩ KHz -40 85 Oscillator frequency Operating free-air temperature, T A mA o C Electrical characteristics over recommended operatng free-air temperature range, Vcc=15V, f= 10 kHz(unless otherwise noted). Parameter Test Conditions* Value MIN MAX 5 5.25 Input regulation Vcc = 7V to 40 V 2 25 Output regulation Io = 1mA to 10mA TA = MIN to MAX 1 15 0.2 1 Vref = 0 35 Output voltage (Vref) Output voltage change with temperature lo = 1mA Short-circuit output current*** 4.75 TYP** Unit V mV % mA Oscillator section (See Figure 1) Parameter Frequency Standard deviation of frequency**** Frequency change with voltage Frequency change with temperature**** Test Conditions* CT=0.01μF, RT=12KΩ All values of Vcc, C T,RT, and TA constant Vcc=7V to 40V, T A=25oC CT=0.01μF, RT=12KΩ, TA = MIN to MAX Value MIN TYP** MAX 10 Unit KHz 10 0.1 % 1 HTC 2008 - Ver. 1.2 4/6 Pulse-Width-Modulation Control Circuits TL494 Electrical characteristics over recommended operating free-air temperature range, Vcc=15V, f=10kHz (unless otherwise noted) Amplifier section (See Figure 2) SYMBOL TEST CONDITIONS Input offset voltage MIN. Vo(pin 3)=2.5V TYP**. MAX. UNIT 2 10 Input offset current Vo(pin 3)=2.5V 25 250 Input bias current Vo(pin 3)=2.5V 0.2 1 Common-mode input voltage range Vcc = 7V to 40V Vo=3V, RL=2KΩ, Vo=0.5~3.5V Open-loop voltage amplification Common-mode rejection ratio Output sink current (pin 3) Output source current (pin 3) ㎂ V -0.3~-2 70 Vo=0.5~3.5V, R L=2KΩ Unity-gain bandwidth ㎷ nA 95 dB 800 kHz Vo= 40V, TA= 25oC VID=-15mV~-5V, V(pin3)=0.7V 65 80 dB 0.3 0.7 mA VID=15mV~5V, V(pin3)=3.5V -2 mA *For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions. ** All typical values except for parameter changes with temperature are at TA =25 oC *** Duration of the short-circuit should not exceed one second. **** Standard deviation is a measure of the statistical distribution about the mean as derived from the formula. ***** Temperature coefficient of timing capacitor and timing resistor not taken into account. Output section Collector off-state current PARAMETER TEST CONDITIONS VCE=40V, Vcc=40V Emitter off-state current VCC=VC=40V,VE=0 Collector-emitter saturation voltage MIN. TYP* 2 MAX. UNIT 100 -100 Common-emitter VE=0, IC=200mA 1.1 1.3 Emitter-follower Vc=15V, IE=-200mA 1.5 2.5 VI=Vref Output control input current 3.5 ㎂ V mA Dead-time control-section (See Figure 1) Input bias current(pin4) PARAMETER TEST CONDITIONS VI=0 to 5.25V Maximum duty cycle, each output VI (pin 4) =0, CT=0.1uF, RT=12KΩ 45 Zero duty cycle 3 Input threshold voltage(pin 4) MIN. TYP* -2 Maximum duty cycle 0 MIN. MAX. UNIT -10 3.3 ㎂ % V PMW comparator section (See Figure 1) PARAMETER TEST CONDITIONS Input threshold voltage (pin3) Zero duty cycle Input sink current (pin 3) V(pin3) = 0.7V TYP* 4 0.3 0.7 MIN. TYP* MAX. UNIT 4.5 V mA Total device PARAMETER Standby supply current Average supply current TEST CONDITIONS Pin 6 at Vref, all other inputs and outputs open VI(pin 4)= 2V VCC=15V VCC=40V MAX. UNIT 6 10 9 15 mA 7.5 HTC 2008 - Ver. 1.2 5/6 Pulse-Width-Modulation Control Circuits TL494 Switching characteristics, TA = 25oC PARAMETER TEST CONDITIONS MIN. Output voltage rise time Common-emitter configuration TYP* Output voltage fall time Output voltage rise time Emitter-follower configuration Output voltage fall time MAX. UNIT 100 200 25 100 100 200 40 100 ns * All typical values except for temperature coefficient are at T A = 25oC tosc - R T 100 10 k 1.0 500 5.0 20 k 50 200 500 1.0 60 60 50 80 40 100 30 120 20 140 10 160 10 100 1.0k 10k FREQUENCY f(Hz) VCE(sat) VCE (V) 1.8 1.9 CE (sat) IC 2.0 1.6 1.4 1.2 1.0 0.8 20 40 TIMING RESISTANCE - 0 70 1.1 1.8 SATURATION VOLTAGE V (sat) (V) CE 80 0 1.0 SATURATION VOLTAGE V Vcc=15V VO=3.0V RL=2.0㏀ 90 - 100k EXCESS PHASE (DEGREES) (dB) VOL 100 OPEN-LOOP VOLTAGE GAIN A OSCILLATOR FREQUENCY t osc (Hz) 500 180 1.0M IE 1.7 1.6 1.5 1.4 1.3 1.2 0.6 1.1 0.4 0 100 200 300 0 COLLECTOR CURRENT Ic ( ) ICC - V CC 10 100 200 300 EMITTER CURRENT IE (mA) SUPPLY CURRENT Icc (mA) 9.0 8.0 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 SUPPLY VOLTAGE Vcc (V) HTC 2008 - Ver. 1.2 6/6