TL494_08

Pulse-Width-Modulation Control Circuits FEATURES ● Complete PWM Power Control Circuitry ● Uncommitted Outputs for 200 mA Sink or Source Current ● Output Control Selects Single-Ended or Push-Pull Operation ● Internal Circuitry Prohibits Double Pulse at Either Output ● Variable Dead-Time Provides Control over Total Range ● Internal Regulator Provides a Stable 5-V Reference Supply,5% ● Circuit Architecture Allows Easy Synchronization Error AMP 1 NONINV INPUT INV INPUT FEEDBAC K DEAD-TIME CONTROL CT RT GND C1 1 2 3 4 5 6 7 8 TL494 SOP16/DIP16 (TOP VIEW) 16 15 14 13 12 11 10 9 NONINV INPUT INV INPUT REF OUT OUTPUT CONTROL Vcc C2 E2 E1 Error AMP 2 ● Moisture Sensitivity Level 3 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 the power supply control circuitry to his application. The TL494 contains an error amplifier, an on-chip adjustable oscillator, a dead-time control comparator, pulse-steering control 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. ORDERING INFORMATION Device TL494D TL494N Package 16 SOP 16 DIP Functional Block Diagram RT CT OUTPUT CONTROL OSCILLATOR Q1 C1 E1 DEAD TIME CONTROL 0.1V DEAD-TIME CONTROL COMPARATOR C1 Q2 C2 E2 PWM COMPARATOR ERROR AMPLIFIER PULSE-STEERING FLIP-FLOP NONINVERTING INPUT INVERTING INPUT + 1 - Vcc ERROR AMPLIFIER NONINVERTING INPUT + 2 INVERTING INPUT FEEDBACK REFERENCE Vref GND 2008 - Ver. 1.2 HTC 1/6 Pulse-Width-Modulation Control Circuits Parameter measurement information TL494 Vcc = 15V Vcc DEAD-TIME FEEDBACK 12KΩ RT CT 0.01uF (+) (-) (+) (-) 50KΩ OUTPUT CONTROL GND REF OUT ERROR C2 E2 150 Ω 2W C1 E1 150 Ω 2W OUTPUT 1 OUTPUT 2 TEST INPUTS TEST CIRCUIT VOLTAGE AT C1 Vcc 0 Vcc VOLTAGE AT C2 0 VOLTAGE AT CT DEAD-TIME CONTROL INPUT THRESHOLD VOLTAGE 0V THRESHOLD VOLTAGE FEEDBACK DUTY CIRCLE 0.7 V 0% MAX 0% FIGURE 1. OPERATIONAL TEST CIRCUIT AND WAVEFORMS 2008 - Ver. 1.2 HTC 2/6 Pulse-Width-Modulation Control Circuits AMPLIFIER UNDER TEST + - TL494 FEEDBACK TERMINAL + Vref - OTHER AMPLIFIER FIGURE 2. AMPLIFIER CHARACTERISTICS 15 V (EACH OUTPUT CIRCUIT) 68 Ω 2W OUTPUT CL=15pF (Includes probe and jig capacitance) t f t r 90% 90% 10% 10% TEST CIRCUIT OUTPUT VOLTAGE WAVEFORM FIGURE 3. COMMON-EMITTER CONFIGURATION 15 V (EACH OUTPUT CIRCUIT) 90% 90% 10% 68 Ω 2W CL=15pF (Includes probe and jig capacitance) TEST CIRCUIT t r 10% t f OUTPUT VOLTAGE WAVEFORM FIGURE 4. EMITTER-FOLLOWER CONFIGURATION 2008 - Ver. 1.2 HTC 3/6 Pulse-Width-Modulation Control Circuits TL494 ABSOLUTE MAXIMUM RATINGS OVER OPERATING FREE-AIR TEMPERATURE RANGE Rating Supply voltage, Vcc Amplifier input voltage Collector output voltage Collector output current Operating free-air temperature range Storage temperature range Lead temperature 1,6 mm from case for 10 seconds Value 41 Vcc +0.3 41 250 -40 to 125 -65 to 150 260 o Unit V mA C RECOMMENDED OPERATING CONDITIONS Parameter Supply voltage, Vcc Amplifier input voltage, Vi Collector output voltage, Vo Collector output current (each transistor) Current into feedback terminal Timing capacitor, C T Timing resistor, R T Oscillator frequency Operating free-air temperature, T A 0.47 1.8 1 -40 Value MIN 7 -0.3 MAX 40 Vcc -2 40 200 0.3 10000 500 300 85 mA nF KΩ KHz o Unit V C Electrical characteristics over recommended operatng free-air temperature range, Vcc=15V, f= 10 kHz(unless otherwise noted). Parameter Output voltage (Vref) Input regulation Output regulation Output voltage change with temperature Short-circuit output current*** Test Conditions* lo = 1mA Vcc = 7V to 40 V Io = 1mA to 10mA TA = MIN to MAX Vref = 0 Value MIN 4.75 TYP** 5 2 1 0.2 35 MAX 5.25 25 15 1 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** 10 10 0.1 1 % MAX Unit KHz 2008 - Ver. 1.2 HTC 4/6 Pulse-Width-Modulation Control Circuits Electrical characteristics over recommended operating free-air temperature range, Vcc=15V, f=10kHz (unless otherwise noted) Amplifier section (See Figure 2) SYMBOL Input offset voltage Input offset current Input bias current Common-mode input voltage range Open-loop voltage amplification Unity-gain bandwidth Common-mode rejection ratio Output sink current (pin 3) Output source current (pin 3) TEST CONDITIONS Vo(pin 3)=2.5V Vo(pin 3)=2.5V Vo(pin 3)=2.5V Vcc = 7V to 40V Vo=3V, RL=2KΩ, Vo=0.5~3.5V Vo=0.5~3.5V, R L=2KΩ Vo= 40V, TA= 25oC VID=-15mV~-5V, V(pin3)=0.7V VID=15mV~5V, V(pin3)=3.5V 65 0.3 -2 -0.3~-2 TL494 MIN. TYP**. 2 25 0.2 MAX. UNIT 10 250 1 ㎷ nA ㎂ V dB kHz dB mA mA 70 95 800 80 0.7 *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 PARAMETER Collector off-state current Emitter off-state current Collector-emitter saturation voltage TEST CONDITIONS VCE=40V, Vcc=40V VCC=VC=40V,VE=0 VE=0, IC=200mA Vc=15V, IE=-200mA VI=Vref MIN. TYP* 2 1.1 1.5 MAX. UNIT 100 -100 1.3 2.5 3.5 ㎂ V mA Common-emitter Emitter-follower Output control input current Dead-time control-section (See Figure 1) PARAMETER Input bias current(pin4) Maximum duty cycle, each output Input threshold voltage(pin 4) TEST CONDITIONS VI=0 to 5.25V VI (pin 4) =0, CT=0.1uF, RT=12KΩ Zero duty cycle Maximum duty cycle 0 MIN. TYP* -2 45 3 3.3 MAX. UNIT -10 ㎂ % V PMW comparator section (See Figure 1) PARAMETER Input threshold voltage (pin3) Input sink current (pin 3) TEST CONDITIONS Zero duty cycle V(pin3) = 0.7V 0.3 MIN. TYP* 4 0.7 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 MIN. TYP* 6 9 7.5 MAX. UNIT 10 15 mA 2008 - Ver. 1.2 HTC 5/6 Pulse-Width-Modulation Control Circuits Switching characteristics, TA = 25oC PARAMETER Output voltage rise time Output voltage fall time Output voltage rise time Output voltage fall time * All typical values except for temperature coefficient are at T A = 25oC TL494 TEST CONDITIONS Common-emitter configuration Emitter-follower configuration MIN. TYP* 100 25 100 40 MAX. UNIT 200 100 200 100 ns tosc - R T 500 (Hz) (dB) 100 90 80 70 60 50 40 30 20 10 0 1.0 5.0 20 k 50 200 500 1.0 1.1 10 100 1.0k 10k 100k TIMING RESISTANCE FREQUENCY f(Hz) osc VOL 100 Vcc=15V VO=3.0V RL=2.0㏀ 0 20 40 60 80 100 120 140 160 180 1.0M EXCESS PHASE (DEGREES) OSCILLATOR FREQUENCY t 10 k 1.0 500 VCE(sat) (sat) (V) - IC (V) 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 0 100 OPEN-LOOP VOLTAGE GAIN A VCE - IE 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0 100 200 300 SATURATION VOLTAGE V SATURATION VOLTAGE V CE CE (sat) 2.0 200 300 10 9.0 SUPPLY CURRENT Icc (mA) 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0 0 5.0 COLLECTOR CURRENT Ic ( ) ICC - V CC EMITTER CURRENT IE (mA) 10 15 20 25 30 35 40 SUPPLY VOLTAGE Vcc (V) 2008 - Ver. 1.2 HTC 6/6