TL494

TL494_08 HTC | Alldatasheet

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Technical content

Pulse-Width-Modulation Control Circuits TL494

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
• 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

ORDERING INFORMATION

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. Functional Block Diagram 2008 - Ver. 1.2 HTC TL494N 16 DIP Device Package TL494D 16 SOP SOP16/DIP16 (TOP VIEW) NONINV INPUT INV INPUT FEEDBAC KDEAD-TIME CONTROL CT RT GND NONINV INPUT INV INPUT REF OUT Vcc OUTPUT CONTROL Error AMP 1 Error AMP 2 OSCILLATOR REFERENCE RT CT DEAD TIME CONTROL 0.1V DEAD-TIME CONTROL COMPARATOR PWM COMPARATOR FEEDBACK ERROR AMPLIFIER ERROR AMPLIFIER NONINVERTING INPUT INVERTING INPUT NONINVERTING INPUT INVERTING INPUT PULSE-STEERING FLIP-FLOP Vcc Vref GND OUTPUT CONTROL

FIGURE 1. OPERATIONAL TEST CIRCUIT AND WAVEFORMS

Pulse-Width-Modulation Control Circuits TL494 ABSOLUTE MAXIMUM RATINGS OVER OPERATING FREE-AIR TEMPERATURE RANGE RECOMMENDED OPERATING CONDITIONS Electrical characteristics over recommended operatng free-air temperature range, Vcc=15V, f= 10 kHz(unless otherwise noted). Oscillator section (See Figure 1) 2008 - Ver. 1.2 HTC 1TA = MIN to MAX Frequency change with temperature** CT=0.01μF, RT=12KΩ, KHz Standard deviation of frequency** 10 % Frequency change with voltage 0.1 Frequency 10 mA Parameter Test Conditions* Value UnitMIN TYP MAX Short-circuit output current* Vref = 0 35 Unit V mV Output voltage change with temperature TA = MIN to MAX 0.2 1 % Operating free-air temperature, TA -40 85 oC Oscillator frequency 1 300 KHz Parameter Value Unit V Vcc=7V to 40V, TA=25oC Unit V mA oC Storage temperature range -65 to 150 Lead temperature 1,6 mm from case for 10 seconds 260 and TA constant All values of Vcc, CT,RT, CT=0.01μF, RT=12KΩ Output regulation Io = 1mA to 10mA 1 15 4.75 5 5.25 Input regulation Vcc = 7V to 40 V 2 25 MIN TYP** MAX Output voltage (Vref) lo = 1mA Parameter Test Conditions* Value Timing resistor, RT 1.8 500 KΩ Timing capacitor, CT 0.47 10000 nF Current into feedback terminal 0.3 mA Collector output current (each transistor) 200 Amplifier input voltage, Vi -0.3 Vcc -2 Collector output voltage, Vo 40 MIN MAX Supply voltage, Vcc 7 40 Amplifier input voltage Vcc +0.3 Collector output voltage 41 Collector output current 250 Operating free-air temperature range -40 to 125 Rating Value Supply voltage, Vcc 41

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) *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 Dead-time control-section (See Figure 1) PMW comparator section (See Figure 1) 2008 - Ver. 1.2 HTC Average supply current VI(pin 4)= 2V 7.5 61 0 mAand outputs open VCC=40V 91 5Standby supply current Pin 6 at Vref, all other inputs VCC=15V mA Total device PARAMETER TEST CONDITIONS MIN. TYP* MAX. UNIT Input sink current (pin 3) V(pin3) = 0.7V 0.3 0.7 MAX. UNIT Input threshold voltage (pin3) Zero duty cycle 4 4.5 V PARAMETER TEST CONDITIONS MIN. TYP*

3.3 VMaximum duty cycle 0Input threshold voltage(pin 4) Zero duty cycle 3

-10 ㎂ Maximum duty cycle, each output VI (pin 4)=0, CT=0.1uF, RT=12KΩ 45 % Input bias current(pin4) VI=0 to 5.25V -2 3.5 mA PARAMETER TEST CONDITIONS MIN. TYP* MAX. UNIT Output control input current VI=Vref 1.1 1.3 VEmitter-follower Vc=15V, IE=-200mA 1.5 2.5 Collector-emitter saturation voltage Common-emitter VE=0, IC=200mA 100 ㎂Emitter off-state current VCC=VC=40V,VE=0 -100 Collector off-state current VCE=40V, Vcc=40V 2 mA PARAMETER TEST CONDITIONS MIN. TYP* MAX. UNIT Output source current (pin 3) VID=15mV~5V, V(pin3)=3.5V -2 dB Output sink current (pin 3) VID=-15mV~-5V, V(pin3)=0.7V 0.3 0.7 mA Common-mode rejection ratio Vo= 40V, TA= 25oC 65 80 dB Unity-gain bandwidth Vo=0.5~3.5V, RL=2KΩ 800 kHz Open-loop voltage amplification Vo=3V, RL=2KΩ, Vo=0.5~3.5V 70 95 1 ㎂ Common-mode input voltage range Vcc = 7V to 40V -0.3~-2 V Input bias current Vo(pin 3)=2.5V 0.2 10 ㎷ Input offset current Vo(pin 3)=2.5V 25 250 nA Input offset voltage Vo(pin 3)=2.5V 2 SYMBOL TEST CONDITIONS MIN. TYP**. MAX. UNIT

Pulse-Width-Modulation Control Circuits TL494 Switching characteristics, TA = 25oC 2008 - Ver. 1.2 HTC * All typical values except for temperature coefficient are at TA = 25oC 100 200 Output voltage fall time 40 100 200 nsOutput voltage fall time 25 100 Output voltage rise time Emitter-follower configuration Output voltage rise time Common-emitter configuration 100 PARAMETER TEST CONDITIONS MIN. TYP* MAX. UNIT 1.0 5.0 20 k 50 200 500 1.0 500 1.0 10 k 100 500 tosc - RT TIMING RESISTANCE OSCILLATOR FREQUENCY t osc (Hz) SATURATION VOLTAGE V CE (sat) (V) VCE - IE 0 100 200 300 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 EMITTER CURRENT IE (mA) SATURATION VOLTAGE V CE (sat) (V) 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 VCE(sat) - IC 0 100 200 300 COLLECTOR CURRENT Ic OPEN-LOOP VOLTAGE GAIN A VOL (dB) 1.1 10 100 1.0k 10k 100k 1.0M FREQUENCY f(Hz) 100 Vcc=15V VO=3.0V RL=2.0㏀ 180 160 140 120 100 EXCESS PHASE (DEGREES) SUPPLY CURRENT Icc (mA) 0 5.0 10 15 20 25 30 SUPPLY VOLTAGE Vcc (V) 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 35 40 ICC - VCC