ABSOLUTE MAXIMUM RATINGS (Unless otherwise noted,all is over operating free air temperature Range) Characteristic Symbol Value Unit

Transcription

1 VOLTAGE MODE PWM CONTROL CIRCUITS DESCRIPTION The UTC9 incorporate on a single monolithic chip all the functions required in the construction of a pulse width modulation control circuit.designed primarily for power supply control, the device offers the systems engineer the flexibility to tailor the power supply control circuitry to its application. The UTC9 contains an error amplifier,current limiting amplifier, an on chip adjustable oscillator, a dead time control comparator,pulse steering control flip flop,a volt,% precision supply regulator,and output control circuits. The error amplifier exhibits a common mode Voltage range from 0.3V to VCC V.The current limit amplifier exhibits a common mode Voltage range from 0.3V to 3V with an offset Voltage of approximately 80 mv in series with the inverting input to ease circuit design requirements. The dead time control comparator has a fixed offset that provides approximately % dead time when externally altered. The onchip oscillator may be bypassed by terminating RT(pin ) to the reference output and providing a sawtooth Input to CT(pin ),or it may be used to drive the common circuits in synchronous multiple rail power supplies. The Uncommitted output transistors provide either commonemitter or emitter follower output capability.each device provides for push pull or single ended output operation,which may be selected through the output control function. the architecture of these devices prohibits the possibility of either being pulsed twice during push pull operation. DIP 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 control Over Total Range *Circuit architecture Allows easy Synchron Ization *Undervoltage Lockout ABSOLUTE MAXIMUM RATINGS (Unless otherwise noted,all is over operating free air temperature Range) Characteristic Symbol Value Unit Supply Voltage(note ) Vcc 0 V Amplifier Input Voltage Vi Vcc+0.3 V Collector Output Voltage Vo V Collector Output Current Ico 0 ma Continuous total dissipation at(or for below) PD 00 mw free air temperature(note ) Operating Temperature Range Topr 0 to 70 C Storage Temperature Range Tstg to 0 C lead Temperature.mm from case for 0 sec. Tcase 300 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. YOUWANG ELECTRONICS CO.LTD V.

2 BLOCK DIAGRAM RECOMMENDED OPERATING CONDITIONS Characteristic Symbol Values min max Unit Supply Voltage Vcc 7 3 V Amplifier Input Voltage Vi 0.3 Vcc V Collector Output Voltage Vo 0 V Collector Output Current(each Transistor) Ic 00 ma Current into feedback If 0.3 ma Timing capacitor CT nf Timing Resistor RT.8 00 kω Oscillator frequency fosc 300 khz Operating free air temperature Ta 0 70 C YOUWANG ELECTRONICS CO.LTD V.

3 ELECTRICAL CHARACTERISTICS (Over recommended operating free air temperature range,vcc=v,f=khz,unless otherwise specified) Characteristic Test Conditions Min Typ Max Unit Reference Section Output voltage Io=mA.9. V Input regulation Vcc=7V to 3V mv Output Regulation Io= to ma mv Output Voltage change with TA=MIN to MAX(note ) 0. % Temperature Short circuit output Current Vref=0 3 ma Characteristic Test Conditions Min Typ Max Unit Oscillator section Frequency CT=0.0µF,RT=0kΩ khz Standard Deviation of Frequency All Values of Vcc CT,RT,TA % constant Frequency Change with Voltage Vcc=7V to 3V,Ta= C 0. % Frequency Change with temperature CT=0.0µF,RT=kΩ, TA=MIN to MAX % Amplifier Section Input offset Voltage Error Vo(pin 3)=.V mv Input offset Current Vo(pin 3)=.V 0 na Input bias Current Vo(pin 3)=.V 0. µa Common mode Input Voltage Range Error Vcc=7V to 3 V 0.3 Vcc V Open Loop Voltage Amplification Vo=3V, Vo=0.V to 3.V 70 9 db Unity Gain Bandwidth 800 khz Common Mode Rejection ratio Error Vcc=3V,TA= C 80 db output sink current(pin 3) VID= mv to V ma V(pin 3)=0.V Output source Current(pin 3) VID=mV to V V(pin 3)=3.V ma Output Section Collector off state current VCE=0V,Vcc=3V 0 µa Emitter off state Current VCC=VC=3V,VE=0 0 µa Collector emitter Saturation Voltage Commonemitter Emitter Follower VE=0,Ic=00mA..3 V Vc=V,IE= 00mA.. Output Control input Current Vi=Vref 3. ma Dead Time Control Section Input bias (pin ) Vi=0 to.v µa Maximum duty cycle,each output VI(pin )=0 % Input threshold Voltage(pin ) Zero duty Cycle V Maximum duty cycle 0 PWM comparator Section Input Threshold Voltage(pin 3) Zero Duty cycle. V Input sink current (pin 3) Vpin 3= 0.7V ma Total Device Standby supply current Vcc=V pin at Vref,all other Inputs and outputs open ma YOUWANG ELECTRONICS CO.LTD V. 3

4 Vcc=0V 9 Average supply current Vpin =V 7. ma Switching Characteristics,Ta= C Output Voltage rise time Common emitter configuration 0 00 ns Output Voltage fall time 0 ns Output Voltage rise time Emitter follower configuration 0 00 ns Output Voltage fall time 0 0 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 3:Duration of the short circuit should not exceed one second. note :Standard deviation is a measure of the statistical distribution the mean as derived from the formula : = N (xn x) n= N YOUWANG ELECTRONICS CO.LTD V.

5 PIN CONFIGURATIONS NONINV INPUT NONINV INPUT INV INPUT INV INPUT FEEDBACK 3 Vref DEAD TIME CONTROL 3 OUTPUT CONTROL CT Vcc RT C GND 7 E C 8 9 E TYPICAL APPLICATION CIRCUIT YOUWANG ELECTRONICS CO.LTD V.

6 TEST CIRCUIT Vcc=V W W TEST INPUTS k DEAD TIME 3 FEEDBACK RT Vcc 0 8 C 9 E 0 OUTPUT 0.0 F CT C E OUTPUT ERROR AMPLIFIER 0k 3 OUTPUT CONTROL Vref OUTPUT 7 VOLTAGE at C VOLTAGE at C VOLTAGE at CT DEAD TIME CONTROL INPUT THRESHOLD VOLTAGE FEEDBACK THRESHOLD VOLTAGE FIG. OPERATIONAL TEST CIRCUIT AND WAVEFORMS ERROR AMPLIFIER Vin FEEDBACK TERMINAL Vref ERROR AMPLIFIER FIG. AMPLIFIER CHARACTERISTICS YOUWANG ELECTRONICS CO.LTD V.

7 EACH OUTPUT CIRCUIT Q Vcc 8 pf % 90% tr tf 90% % Vc EACH OUTPUT CIRCUIT Q 8 Vcc pf % 90% tr tf 90% % Ve FIG. 3 COMMON EMITTER CONFIGURATION FIG. EMITTER FOLLOWER CONFIGURATION TYPICAL PERFORMANCE CHARACTERISTICS Oscillator Frequency (Hz) 3 CT= F Vcc=V T a=0~70 CT=0.00 F CT=0.0 F CT=0. F Voltage Amplification (db) Vcc=V V =3V T a= 3 RT(Timing Resistance) ( ) 0 3 Frequency (Hz) FIG. Oscillator Frequency and Frequency Variation Vs Timing Resistance Fig. Amplifier Voltage Amplification YOUWANG ELECTRONICS CO.LTD V. 7

8 PACKAGE DIMENSIONS DIP 300. Unit: mm SOP.7 Unit: mm YOUWANG ELECTRONICS CO.LTD V. 8