MC34063S

MC34063 DC TO DC CONVERTER CONTROLLER DESCRIPTION „ The MC34063 is a monolithic regulator subsystem, intended for use as DC to DC converter. This device contains a temperature compensated band gap reference, a duty-cycle control oscillator, driver and high current output switch. It can be used for step down, step-up or inverting switching regulators as well as for series pass regulators. MC34063D DIP-8 FEATURES „ * Operation from 3.0V to 40V. * Short circuit current limiting. * Low standby current. * Output switch current of 1.5A without external transistors. * Frequency of operation from 100Hz to 100kHz. * Step-up, step-down or inverting switch regulators. „ PIN CONFIGURATION „ PIN DESCRIPTION PIN NO 1 2 3 4 6 PIN NAME Switch Collector Switch Emitter Timing Capacitor GND Comparator Inverting Input VCC 7 IPEAK Sense I 8 Driver Collector I 5 www.slkormicro.com I/O I O I MC34063S SOP-8 DESCRIPTION Internal Darlington pairs TI collector Internal Darlington pairs TI emitter The value of selected capacitor controls the internal oscillator run rate Inverting input of comparator which can set & initiate the Darlington pairs output switch Current sense input to monitor the voltage drop across an external resistor placed in series with VCC Internal Darlington pairs TI collector 1 MC34063 „ BLOCK DIAGRAM E Switch Collector T2 1 S Q R T1 Switch Emitter 8 Drive Collector 7 IPEAK Sense 6 Vcc 5 Comparator Inverting Input D C 2 A Is CT OSCILLATOR Timing Capacitor 3 COMP. GND „ 4 1.25VREF B ABSOLUTE MAXIMUM RATINGS (Ta=25°C ) PARAMETER Supply Voltage Comparator Input Voltage Range Switch Collector Voltage Switch Emitter Voltage Switch Collector to Emitter Voltage Driver Collector Voltage Switch Current RATINGS UNIT 40 V -0.3 ~ +40 V 40 V 40 V 40 V 40 V 1.5 A DIP-8 1250 Power Dissipation (Ta=25°C) PD mW SOP-8 625 Junction Temperature TJ +150 °C Operating Temperature TOPR 0 ~ +70 °C Storage Temperature TSTG -65 ~ +150 °C Note: Absolute maximum ratings are those values beyond which the device which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied. „ SYMBOL VCC VIN(COMP) VC(SW) VE(SW) VCE(SW) VC(DR) ISW THERMAL DATA PARAMETER Junction-to-Ambient www.slkormicro.com SYMBOL DIP-8 SOP-8 2 θJA RATINGS 100 160 UNIT ℃/W MC34063 „ ELECTRICAL CHARACTERISTICS (VCC=5.0V, Ta=0~+70°C, unless otherwise specified.) PARAMETER Oscillator Charging Current Discharging Current Oscillator Amplitude Discharge to Charge Current Ratio Current limit Sense Voltage Output Switch Saturation Voltage 1(Note) Saturation Voltage 2(Note) DC Current Gain(Note) Collector Off State Current(Note) Comparator Threshold Voltage Threshold Voltage Line Regulation Input Bias Current Total Device SYMBOL ICHG IDISCHG VOSC K VSENSE VCE(SAT)1 VCE(SAT)2 GI (DC) IC(OFF) VTHD VTHD II(BIAS) TEST CONDITIONS VCC=5 to 40V, Ta=25°C VCC=5 to 40V, Ta=25°C Ta=25°C V7=VCC, Ta=25°C ICHG=IDISCHG, Ta=25°C MIN TYP MAX UNIT 22 140 31 190 0.5 6.1 300 42 260 7.5 350 mV 0.95 0.45 180 0.01 1.3 0.7 V V 100 μA 1.21 1.24 1.29 2.0 5.0 50 400 V mV nA 5.2 250 ISW=1.0A, VC(DRIVER)=VC(SW) ISW=1.0A, VC(DRIVER)=50mA ISW=1.0A, VCE=5.0V, Ta=25°C VCE=40.0V, Ta=25°C VCC=3 ~ 40V VIN=0V 50 VCC=5~40V, CT=0.001 V7=VCC, VC>VTHD, Pin2=GND Note: Output switch tests are performed under pulsed conditions to minimize power dissipation. Supply Current „ ICC 2.7 4.0 μA μA V mA STEP-UP CONVERTER(Cont.) 170μH L 1 8 180 S Q Q2 R Q1 7 2 1N5819 IPK RSC 0.22 VIN12V OSC 6 + 100 CT 3 CT VCC + - Comp. 1.25V REF REG 5 1500pF 4 1.0μH R2 R1 2.2k 47k 330 + CO VOUT 28V/175mA VOUT + 100 Optional Filter www.slkormicro.com 3 MC34063 STEP-DOWN CONVERTER(Cont.) „ „ VOLTAGE INVERTING CONVERTER www.slkormicro.com 4 MC34063 „ DESIGN FORMULA TABLE CALCULATION tON tOFF STEP-DOWN STEP-UP VOLTAGE-INVERTING VOUT + VF VIN - VCE(SAT) (tON+tOFF)MAX CT 4x10-5 tON ISW 2IOUT(MAX) RS 0.3/ISW 4x10-5 tON 4x10-5 tON 0.3/ISW 0.3/ISW L(MIN) IOUT tON VRIPPLE(P-P) CO VCE(SAT) - Saturation voltage of the output switch. VF - Forward voltage drop of the ringback rectifier. The following power supply characteristics must be chosen: - Nominal input voltage. VIN VOUT - Desired output voltage, VOUT =1.25(1+R2/R1) IOUT - Desired output current. FMIN - Minimum desired output switching frequency at the selected values for VIN and IOUT. VRIPPLE(P-P) - Desired peak-to-peak output ripple voltage. In practice, the calculated value will need to be increased due to the capacitor equivalent series resistance and board layout. The ripple voltage should be kept to a low value since it will directly effect the line and load regulation. www.slkormicro.com 5 MC34063 „ TYPICAL CHARACTERISTICS www.slkormicro.com 6