LINEAR INTEGRATED CIRCUIT

Transcription

1 VOLTAGE MODE PWM CONTROL CIRCUIT DESCRIPTION The incorporates all the functions required in the construction of a pulse-width modulation switching circuit. Designed primarily for switching power supply control or DC- DC convectors, it offers the systems engineer the flexibility to tailor control circuitry to its own application. SOP- FEATURES *Complete PWM power control circuitry *Uncommitted outputs for 00 ma sink or source current *Output control selects single ended or push pull operation *Internal circuitry prohibits double pulses over total range *Easy synchronization DIP- ABSOLUTE MAXIMUM RATINGS(Unless otherwise noted all is over operating free air temperature range) PARAMETER SYMBOL VALUE UNIT Supply Voltage(note ) V CC 0 V Amplifier Input Voltage V I V CC +0. V Collector Output Voltage V O 0 V Collector Output Current I CO 0 ma Continuous Total Dissipation at(or for below) P D 000 mw C Free Air Temperature(note ) Operating Temperature Range T opr 0 TO 70 C Storage Temperature Range T stg - TO 0 C Lead Temperature.mm from Case for 0 Sec. T case 0 C note : All voltage values, except differential voltages are with respect to the network ground terminal. note :For operation above C free-air temperature, the dissipation derates with 9.mW/ C.

2 BLOCK DIAGRAM RT CT oscillator Pulse Steering Flip-Flop T Input control 8 C 9 E C 0 E dead time control dead time comparator PWM comparator V reference regulation 0.7mA Error Amplifier Error Amplifier 7 GND RECOMMENDED OPERATING CONDITIONS PARAMETER SYMBOL VALUE UNIT MIN MAX Supply Voltage 7 0 V Amplifier Input Voltage Vi V Collector Output Voltage Vo 0 V Collector Output Current(each Transistor) Ic 00 ma Current into Feedback If 0. ma Timing Capacitor CT nf Timing Resistor RT.8 00 kω Oscillator Frequency fosc 00 khz Operating Free-Air Temperature Ta 0 70 C ELECTRICAL CHARACTERISTICS (Over recommended operating free-air temperature range,vcc=v,f=khz,unless otherwise specified) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Reference Section Output Voltage Io=mA.7. V Input Regulation =7V to 0V mv Output Regulation Io= to 0mA mv Output Voltage Change with TA=MIN to MAX(note ) 0. % Temperature Short-Circuit Output Current =0 ma Oscillator Section Frequency CT=0.0µF,RT=kΩ 0 khz

3 PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Standard Deviation of Frequency All Values of CT, RT, TA 0 % constant Frequency Change with Voltage =7v to 0V,Ta= C 0. % Frequency Change with CT=0.0µF,RT=kΩ, TA=MIN % Temperature to MAX Amplifier Section Input Offset Voltage Error Vo(pin )=.V 0 mv Input Offset Current Vo(pin )=.V 0 na Input Bias Current Vo(pin )=.V 0. µa Common-Mode Input Voltage Range Error =7V to 0 V -0. to - Open-Loop Voltage Amplification Vo=V, Vo=0.V to.v 70 9 db Unity-Gain Bandwidth 800 khz Common-Mode Rejection Ratio Error =0V,TA= C 80 db Output Sink Current(pin ) VID=-mV to -V ma V(pin )=0.V Output source Current(pin ) VID=mV to -V V(pin )=.V - ma Output Section Collector off-state current VCE=0V,=0V 00 µa Emitter off-state Current VCC=VC=0V,VE=0-00 µa Collector -emitter Saturation Voltage Commonemitter Emitter- Follower VE=0,Ic=00mA.. V Vc=V,IE=-00mA.. Output Control Input Current Vi=. ma Dead Time Control Section Input bias (pin ) Vi=0 to.v - -0 µa Maximum duty cycle, each output VI(pin 0=0 % Input threshold Voltage(pin ) Zero duty Cycle. V Maximum duty cycle 0 PWM comparator Section Input Threshold Voltage(pin ) Zero Duty cycle. V Input Sink Current (pin ) Vpin = 0.7V ma Total Device Standby Supply Current =V pin at,all other Inputs and 0 ma outputs open =0V 9 Average supply current Vpin =V 7. ma Switching Characteristics,Ta= C Output Voltage Rise Time Common-emitter configuration ns Output Voltage Fall Time 00 ns Output Voltage Rise Time Emitter-follower configuration ns Output Voltage Fall Time 0 00 ns note :All typical Values except for temperature coefficient are at Ta= C. note :For conditions shown as MIN or MAX, use appropriate value under recommended operating conditions. note :Duration of the short-circuit should not exceed one second. V

4 note : Standard deviation is a measure of the statistical distribution the mean as derived from the formula : σ= ΣN (xn-x) n= N- TEST CIRCUIT =V TEST INPUTS kω 0.0 µf DEAD-TIME RT CT ERROR AMPLIFIER W 0 Ω C 8 E 9 C E 0 W 0 Ω 0kΩ CONTROL GND 7 VOLTAGE at C VOLTAGE at C VOLTAGE at CT DEAD-TIME CONTROL INPUT THRESHOLD VOLTAGE THRESHOLD VOLTAGE FIG. OPERATIONAL TEST CIRCUIT AND WAVEFORMS

5 Vin ERROR AMPLIFIER TERMINAL ERROR AMPLIFIER FIG. AMPLIFIER CHARACTERISTICS EACH CIRCUIT 8Ω pf 0% tr tf 0% Vc EACH CIRCUIT 8Ω pf 0% tr tf 0% Ve FIG. COMMON-EMITTER CONFIGURATION FIG. EMITTER -FOLLOWER CONFIGURATION PIN CONFIGURATIONS NONINV INPUT NONINV INPUT INV INPUT INV INPUT DEAD-TIME CONTROL CONTROL CT RT C GND 7 0 E C 8 9 E

6 TYPICAL PERFORMANCE CHARACTERISTICS 0 0 =V Ta=0~70 XC CT=0.00 µf =V V=V Ta= XC Oscillator Frequency (Hz) CT= µf 0 CT=0.0 µf CT=0. µf RT(Timing Resistance) ( Ω ) 0 0 Voltage Amplification (db) Frequency (Hz) 0 0 FIG. Oscillator Frequency and Frequency Variation Fig. Amplifier Voltage Amplification Vs Timing Resistance