TL494 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

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 am plifier 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 RT (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 HTC TL494N 18 DIP Device Package TL494D 16 SOP 145 Mar. 2006-Rev06 SOP16/DIP16 (TOP VIEW) NONINV INPUT INV INPUT FEEDBACK DEAD-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) HTC 148 0.47 10000 Timing resistor, RT 1.8 500 Operating free-air temperature, TA Rating Value Unit 250 0 to 70 mA V oC-65 to 150 Amplifier input voltage, Vi 260 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 Vcc +0.3 Collector output voltage, Vo Collector output current (each transistor) Current into feedback terminal Timing capacitor, C T Parameter MIN MAX 74 0 Value Supply voltage, Vcc 0.3 -0.3 Vcc -2 Oscillator frequency 1 300 KHz 07 0 oC Unit V mA KΩ nF 200 Value MIN TYP** MAX V mV Unit mA 4.75 5 5.25 22 5 11 5 0.2 1 Parameter Test Conditions* Output voltage (Vref) Input regulation Output regulation Output voltage change with temperature Short-circuit output current* lo = 1mA Vcc = 7V to 40 V Io = 1mA to 10mA T A = MIN to MAX Vref = 0 UnitMIN TYP MAX KHz All values of Vcc, CT,RT, %0.1Vcc=7V to 40V, TA=25oC Frequency CT=0.01μF, RT=12KΩ Parameter Test Conditions* Value CT=0.01μF, RT=12KΩ, Standard deviation of frequency** TA = MIN to MAX Frequency change with voltage Mar. 2006-Rev06 Frequency change with temperature** and TA constant

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) HTC Standby supply current Pin 6 at Vref, all other inputs and outputs open Average supply current 149 UNIT VCC=15V VCC=40V VI(pin 4)= 2V mA15 7.5 TEST CONDITIONS MIN. TYP* MAX. Total device PARAMETER PARAMETER Input threshold voltage (pin3) Zero duty cycle Input sink current (pin 3) V(pin3) = 0.7V TEST CONDITIONS Input threshold voltage(pin 4) Zero duty cycle VMaximum duty cycle Input bias current(pin4) VI=0 to 5.25V Maximum duty cycle, each output VI (pin 4)=0, CT=0.1uF, RT=12KΩ 1.5 2.5 1.3 PARAMETER Output control input current Collector-emitter saturation voltage Common-emitter Emitter-follower V VI=Vref VCC=VC=40V,VE=0 VE=0, IC=200mA Vc=15V, IE=-200mA 1.1 PARAMETER Collector off-state current Emitter off-state current 0.7 TYP* MAX. -100 TEST CONDITIONS VCE=40V, Vcc=40V mA Output source current (pin 3) VID=15mV~5V, V(pin3)=3.5V -2 mA Output sink current (pin 3) VID=-15mV~-5V, V(pin3)=0.7V 0.3 kHz Common-mode rejection ratio Vo= 40V, TA= 25oC 65 80 dB Unity-gain bandwidth Vo=0.5~3.5V, RL=2KΩ 800 Open-loop voltage amplification 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 Input offset voltage Input offset current Input bias current Common-mode input voltage range V-0.3~-2 nA 61 0 0.3 mA 0.7 TYP* MAX. UNIT 4 4.5 V MIN. 3 3.3 -2 -10 TEST CONDITIONS MIN. TYP* MAX. UNIT 3.5 mA UNIT 2 100 MIN. 70 95 dB 0.2 1 ㎂ 25 250 UNIT 21 0 ㎷ MAX.SYMBOL TEST CONDITIONS MIN. TYP**. Mar. 2006-Rev06

Pulse-Width-Modulation Control Circuits TL494 Switching characteristics, T A = 25oC HTC * All typical values except for temperature coefficient are at TA = 25oC Output voltage fall time 40 Output voltage rise time Emitter-follower configuration 100 UNIT Output voltage rise time Common-emitter configuration 100 200 nsOutput voltage fall time PARAMETER TEST CONDITIONS MIN. TYP* 100 MAX. 25 100 200 150 Mar. 2006-Rev06 1.0 k 5.0 k 20 k 50 k 200 500 1.0 500 1.0 k 10 k 100 500 tosc - R T TIMING RESISTANCE RT(Ω) OSCILLATOR FREQUENCY t osc (Hz) SATURATION VOLTAGE V CE (sat) (V) VCE - I E 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) - I C 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 - V CC