DC-DC Converter Control Circuits FEATURES ● OUTPUT SWITCH CURRENT IN EXCESS OF 1.5A MC34063A 8 SOP/ 8 DIP PIN Configulation ● 2% REFERENCE ACCURACY ● LOW QUIESCENT CURRENT:2.5mA(TYP.) ● OPERATING FROM 3V TO 40V ● FREQUENCY OPERATION TO 100KHz ● ACTIVE CURRENT LIMITING ● MOISTURE SENSITIVITY LEVEL 3 ● MC34063AG is Halogen Free products SOP-8 PKG APPLICATION ● Battery Chargers ● NICs / Switches / Hubs ● ADSL Modems ● Negative Voltage Power Supplies DIP-8 PKG Switch Collector 1 8 Driver Collector Switch Emitter 2 7 Ipk Sense Timing Capacitor 3 6 Vcc Ground 4 5 Comparator Inverting Input ORDERING INFORMATION Device MC34063AD MC34063AGD MC34063AN Package SOP-8 DIP-8 DESCRIPTION The MC34063A series is a monolithic control circuit delivering the main functions for DC-DC voltage converting. The device contains an intermal temperature compensated reference, comparator, duty cycle controlled oscillator with an active current limit circuit driver and high current output switch. Output voltage is adjustable through two external resistors with a 2% reference accuracy. Employing a minimum number of external components the MC34063A devices series is designed for Step-Down, Step-Up and Voltage-lnverting applications. HTC May. 2009 - Rev. 1.2 −1− DC-DC Converter Control Circuits MC34063A BLOCK DIAGRAM Driver Collector 8 s Q Q2 1 Switch Collector 2 Switch Emitter 3 Timing Capacitor 4 GND Q1 R 7 Ipk Sense Ipk Oscillator Vcc 6 Comparator 1.25V Reference Regulator + Comparator lnverting input 5 THERMAL DATA SYMBOL Rthi-amb PARAMETER * Thermal Resistance Junction-ambient ( ) Max DIP-8 SOP-8 UNIT 100 160 ℃/w VALUE UNIT 50 V -0.3 to 40 V (*) This Value depends from thermal design of PCB on which the device is mounted. ABSOLUTE MAXIMUM RATINGS SYMBOL PARAMETER Vcc Power Supply Voltage Vir Comparator input Voltage Range VSWC Switch Collector Voltage 40 V VSWE Switch Emitter Voltage (VSWC=40V) 40 V VCE Switch Collector to Emitter Voltage 40 V Vdc Driver Collector Voltage 40 V Idc Driver Collector Current 100 ㎃ Isw Switch Current 1.5 A Ptot Power Dissipation at Tamb=25℃(for Plastic Package) 1.25 W (for SOIC Package) 0.625 Top Tstg Operating Ambient Temperature Range -30 to +125 ℃ Storage Temperature Range -40 to +150 ℃ Absolute Maximum Rating are those values beyond which damage to the device may occur. Functional operation under these condition is not implied. HTC May. 2009 - Rev. 1.2 −2− DC-DC Converter Control Circuits MC34063A ELECTRICAL CHARACTERISTICS (Refer to the test circuits, VCC=5V, Ta=TLOW to THIGH, unless otherwise specified, see note 2) OSCILLATOR SYMBOL PARAMETER FOSC Frequency Ichg Charge Current TEST CONDITIONS o Vpin5= 0 V ,CT= 1nF ,T a= 25 C VCC= 5 to 40V ,T a= 25oC Discharge Current Idischg/Ichg Discharge to Charge Current Ratio Vipk(sense) Current Limit Sense Voltage TYP. 33 MAX. UNIT 42 KHz 24 35 42 ㎂ 140 220 260 ㎂ Pin 7= V CC ,Ta= 25 C 5.2 6.5 7.5 Ichg= Idischg ,Ta= 25oC 250 300 350 TEST CONDITIONS ISW = 1A ,Pins 1,8 connected MIN. TYP. 1.0 o Idischg MIN. 24 VCC= 5 to 40V ,T a= 25 C o ㎷ OUTPUT SWITCH SYMBOL PARAMETER VCE(sat) Saturation Voltage, MAX. UNIT 1.3 V Darlington connection VCE(sat) 0.45 ISW = 1A ,Rpin8= 82Ω to VCC, Saturation Voltage 0.7 V 100 ㎂ Forced β ~ 20 hFE DC Current Gain IC(off) Collector Off-State Current ISW = 1A, VCE= 5V, T a= 25oC VCE= 40V 50 75 0.01 COMPARATOR SYMBOL PARAMETER Vth Threshold Voltage Regline IIB Threshold Voltage Line Regulation Input Bias Current TEST CONDITIONS Ta= 25oC Ta= TLOW to THIGH MIN. 1.225 1.21 VCC= 3 to 40V VIN= 0V TYP. 1.25 1 -5 MAX. UNIT 1.275 V 1.29 V 5 ㎷ -400 ㎁ TYP. 1.4 MAX. UNIT 4 ㎃ TOTAL DEVICE SYMBOL PARAMETER ICC Supply Current TEST CONDITIONS VCC= 5 to 40V, CT=1㎋ MIN. Pin7= VCC ,Vpin5>Vth, Pin2=GND Remaining pins open for MC34063A Notes: 1) Maximum package power dissipation limit must be observed. 2) TLOW= '-30℃, THIGH= '+125℃ 3) If Darlington configuration is not used, care must be taken to avoid deep saturation of output switch. The resulting switch-off time may be adversely affected. In a Darlington configuration the following output driver condition is suggested: Forced β of output current switch= CI OUTPUT /(ICDRIVER -1㎃*)≥10 * Current less due to a built in 1KΩ antileakage resistor. HTC May. 2009 - Rev. 1.2 −3− DC-DC Converter Control Circuits MC34063A TYPICAL ELECTRICAL CHARACTERISTICS Output Switch ON-OFF Time vs Oscillator Emitter Follower Configuration Output Saturation Voltage vs Emitter Current Timing Capacitor VCE(sat) (V) Ton Toff (㎲) 1.75 VCC=5V Pin1,7,8=VCC Pins3,5=GND Ta=25℃ 1.70 1.65 200 150 1.60 VCC=5V Pin7=VCC Pin5=GND Ta=25℃ Ton 100 1.55 1.50 Toff 50 1.45 1.40 0 0 400 1200 800 IE(㎃) Common Emitter Configuration Output Switch Saturation Voltage vs Collector Current VCE(sat) (V) 0.1 0.01 CT(㎋) 1 Darlington Configuration Collector Emitter Saturation Voltage (VCE(sat)) vs Temperature VCE(sat) (㎷) Darlington Connection 1.0 1000 0.8 950 VCC=5V Pin7=VCC Pins2,3,5=GND Ta=25℃ 0.6 0.4 0.2 850 800 0 400 IC=1A 900 Forced β =20 0 VCC=5V 800 1200 750 -40 1C(㎃) 0 80 120 TJ(℃) Current Limit Sense Voltage Voltage (Vipk) vs Temperature Power Collector Emitter Ssturation Voltage (VCE(sat)) vs Temperature Vipk (㎷) VCE(sat) (㎷) 600 320 VCC=5V 550 40 MC34063A IC=1A 310 500 300 450 290 400 280 VCC=5V 350 -40 0 40 80 120 270 -40 TJ(℃) Ichg=Idischg 0 40 80 120 TJ(℃) HTC May. 2009 - Rev. 1.2 −4− DC-DC Converter Control Circuits MC34063A TYPICAL ELECTRICAL CHARACTERISTICS (Continued) Reference Voltage vs Temperature Bias Current vs Temperature Vref (V) IBias (㎁) 1.265 10 VCC=5V CII to GND VCC=5V 1.260 8 1.255 6 1.250 4 1.245 2 1.240 -40 0 40 80 120 0 -40 TJ(℃) Supply Current vs Temperature ICC ICC (㎃) 5 4.0 VCC=5V CT=1㎋ 80 120 TJ(℃) TJ= 25℃ CT= 1㎋ 3.5 3 3.0 2 2.5 1 2.0 0 -40 40 Supply Current vs Input Voltage (㎃) 4 0 1.5 0 40 80 120 0 TJ(℃) 10 20 30 40 Vin(V) HTC May. 2009 - Rev. 1.2 −5− DC-DC Converter Control Circuits MC34063A TYPICAL APPLICATION CIRCUIT Step-Up Converter L1 170μH R3 1 8 DRC SWC Ipk SWE 180Ω 7 Rsc 2 6 Vcc TC CII GND D1 BYV10-40 3 0.22Ω 5 VIN 12V + C2 100㎌ 4 C3 VOUT 1.5㎋ 25V/175㎃ MC34063A R1 R2 2.2KΩ + C1 44KΩ 330㎌ Step-Down Converter 1 8 DRC SWC BYV10-40 7 Rsc 2 Ipk 0.33Ω SWE 6 Vcc TC CII GND 5 VIN 25V + C2 100㎌ D1 3 L 4 C3 220μH 470㎊ MC34063A R1 R2 1.2KΩ 3.5KΩ + C1 VOUT 5V/0.5A 470㎌ HTC May. 2009 - Rev. 1.2 −6− DC-DC Converter Control Circuits MC34063A Step-Up With External NPN Switch 8 VOUT 1 S Q2 Q + Q1 R 2 7 Rsc 3 Ipk Oscillator VIN 6 comparator 1.25V + 4 Reference - Regulator 5 Voltage Inverting Converter 1 8 DRC SWC 7 R3 L1 2 Ipk SWE 0.22Ω 90μH 6 3 Vcc TC 5 VIN 4.5V to 5V + C2 D1 4 CII GND BYV10-40 C3 1.5㎋ 100㎌ MC34063A R2 R1 VOUT 8.2KΩ 953Ω C1 + -12V /100㎃ 1000㎌ HTC May. 2009 - Rev. 1.2 −7− DC-DC Converter Control Circuits MC34063A Step-Down With External NPN Switch 8 1 S Q Q2 Q1 R 2 7 Rsc VOUT 3 Ipk Oscillator + 6 VIN comparator 1.25V + 4 Reference - Regulator 5 Step-Down With External PNP Switch 8 1 S Q Q2 Q1 R + VOUT 2 7 Rsc VIN 3 Ipk Oscillator 6 comparator + - 1.25V 4 Reference Regulator 5 HTC May. 2009 - Rev. 1.2 −8− DC-DC Converter Control Circuits MC34063A Voltage Inverting With External NPN Switch 8 1 S Q Q2 Q1 R 2 7 Rsc Ipk Oscillator 6 VIN VOUT 3 + comparator 1.25V + - 4 Reference Regulator 5 Voltage Inverting With External PNP Saturated Switch 8 1 S Q2 Q VOUT Q1 R + 2 7 Ipk Oscillator Rsc VIN 6 3 comparator + - 1.25V Reference 4 Regulator 5 HTC May. 2009 - Rev. 1.2 −9− DC-DC Converter Control Circuits MC34063A Dual Output Voltage + +12V GND 8 + 1 S Q Q2 -12V Q1 R 2 7 Rsc Ipk Oscillator comparator 6 VIN 3 1.25V + - 4 Reference Regulator 5 Higher Output Power, Higher Input Voltage + Isolated from input +VOUT -VOUT 8 + 1 S Q R 2 7 7 VIN Rsc Ipk Oscillator 6 3 comparator 1.25V + - Reference 4 Regulator 5 HTC May. 2009 - Rev. 1.2 − 10 − DC-DC Converter Control Circuits MC34063A Design Formula Table Calculation Step-Up ton/toff Vout + VF - Vin(min) Vin(min) - Vsat ( ( ton +1 toff Co Vin(min) - Vsat Ipk(switch) 9 )x -5 4.0 X 10 ton ) 4.0 X 10 ton 2Iout(max) 0.3 / Ipk(switch) Rsc f min -5 4.0 X 10 ton 2Iout(max) 1 f min -5 Ipk(switch) |Vout| + VF Vin + Vsat 1 f min CT Voltage-Inverting Vout + VF Vin(min) - Vsat 1 (ton/toff)max L(min) Step-Down 2Iout(max) 0.3 / Ipk(switch) ton(max) ( Iout ton Vripple(pp) Vin(min)-Vsat-Vout Ipk(switch) ) xt Ipk(switch)(ton + toff) 8Vripple(pp) ( ton +1 toff ) 0.3 / Ipk(switch) on(max) ( Vin(min) - Vsat Ipk(switch) 9 )x ton(max) Iout ton Vripple(pp) TERMS AND DEFINITIONS Vsat - Saturation voltage of the output switch. VF - Forward voltage drop of the output rectifier. The following power supply characteristics must be chosen: Vin - Nominal input voltage. Vout - Desired output voltage. Iout - Desired output current. f min- Minimum desired output switching frequency at the selected values of V in and IO. Vripple(p-p) – Desired peack-to-peack output ripple voltage. In practice the calculated capacitor value will need to be increased due to its equivalent series resistance and board layout. The ripple voltage should be kept to a low value since it will directly affect the line and load regulation. HTC May. 2009 - Rev. 1.2 − 11 −