GM34063 PRELIMINARY 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT 3.0V to 40V input Adjustable Output Voltage Current Limiting Output Switch Current to 1.5A Low Standby Current Operating Frequency to 100kHz Precision 2% Reference PIN CONNECTIONS Switch Collector Switch Emitter Timing Capacitor The GM34063 has all the functions required for DC-to-DC converters: an internal temperaturecompensated reference, comparator, controlled duty cycle oscillator with an active current limit circuit, driver, and high-current output switch. The 34063 designed for step-down, step-up and voltage-inverting applications using a minimum number of external components. GND 8 7 6 5 1 2 3 4 Driver Collector Ipk Sense VCC Comparator Inverting unit (Top View) Applications: CD-ROM Motherboards SMPS Power Supply Battery Chargers SCHEMATIC DIAGRAM Driver Collector 1 8 S Ipk Sense Q1 100 2 Switch Emitter CT 6 3 Comparator + Timing Capacitor 1.25V Reference Regulator Comparator Inverting unit Q2 R 7 Ipk Oscillator VCC Q Switch Collector 5 4 GND (Bottom View) * The GM34063 has 51 active transistors on-chip. Revision 1, May 2002 1 www.gammamicro.com GM34063 PRELIMINARY 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT Absolute Maximum Ratings Rating Symbol Value Unit Power Supply Voltage V CC 40 V dc Comparator Input Voltage Range VIR –0.3 to +40 V dc Switch Collector Voltage VC(switch) 40 V dc Switch Emitter Voltage (VPin 1 = 40 V) VE(switch) 40 Vc VCE(switch) 40 V dc Driver Collector Voltage VC(driver) 40 V dc Driver Collector Current (Note 1) IC(driver) 100 mA Switch Current ISW 1.5 A Power Dissipation and Thermal Characteristics Plastic Package, P, P1 Suffix TA = 25°C Thermal Resistance SOIC Package, D Suffix TA = 25°C PD R2JA 1.25 100 W °C/W PD R2JA 625 160 mW °C/W Operating Junction Temperature TJ +150 °C Operating Ambient Temperature Range TA 0 to +70 °C Storage Temperature Range Tstg –65 to +150 °C Switch Collector to Emitter Voltage Thermal Resistance Note 1. Maximum package power dissipation limits must be observed. Revision 1, May 2002 2 www.gammamicro.com GM34063 PRELIMINARY 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT ELECTRICAL CHARACTERISTICS (VCC = 5.0 V, TA = Tlow to Thigh unless otherwise specified) Characteristics Symbol Min Typ Max Unit Frequency (VPin 5 = 0 V, CT = 1.0 nF, TA = 25°C) fosc 24 33 42 kHz Charge Current (VCC = 5.0 V to 40 V, TA = 25°C) Ichg 24 35 42 :A Idischg 140 220 260 :A OSCILLATOR Discharge Current (VCC = 5.0 V to 40 V, TA = 25°C) Discharge to Charge Current Ratio (Pin 7 to VCC, TA = 25°C) Idischg/Ichg 5.2 6.5 7.5 – Current Limit Sense Voltage (I chg = I dischg, TA = 25°C) Vipk(sense) 250 300 350 mV Saturation Voltage, Darlington Connection ( ISW = 1.0 A, Pins 1, 8 connected) VCE(sat) – 1.0 1.3 V Saturation Voltage (Note 3) (ISW = 1.0 A, RPin 8 = 82 S to VCC, Forced $ .20) VCE(sat) – 0.45 0.7 V DC Current Gain (ISW = 1.0 A, VCE = 5.0 V, TA = 25°C) hFE 50 75 – – Collector Off–State Current (VCE = 40 V) IC(off) – 0.01 100 :A OUTPUT SWITCH (Note 2) COMPARATOR Vth Threshold Voltage V TA = 25°C 1.225 1.25 1.275 TA = Tlow to Thigh 1.210 - 1.29 Reg line - 1.4 5.0 mV IIB - -20 -400 nA ICC - - 4.0 mA Threshold Voltage Line Regulation (V CC = 3.0 V to 40 V) Input Bias Current (Vin = 0 V) TOTAL DEVICE Supply Current (VCC = 5.0 V to 40 V, CT = 1.0 nF, Pin 7 = VCC, VPin 5 > Vth, Pin 2 = Gnd, remaining pins open) Note 2. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible. Note 3. If the output switch is driven into hard saturation (non–Darlington configuration) at low switch currents (#300 mA) and high driver currents ($30 mA), it may take up to 2.0 µs for it to come out of saturation. This condition will shorten the off time at frequencies $30 kHz, and is magnified at high temperatures. This condition does not occur with a Darlington configuration, since the output switch cannot saturate. If a non–Darlington configuration is used, the following output drive condition is recommended: Forced β of output switch : IC output $10 IC driver – 7.0 mA * * The 100 Ω resistor in the emitter of the driver device requires about 7.0 mA before the output switch conducts. Revision 1, May 2002 3 www.gammamicro.com GM34063 PRELIMINARY 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT Test C onditions R esults Li ne Regulati on Vin = 8.0 V to 16 V, IO = 175 mA 30 mV = ±0.05% Load Regulati on Vin = 12 V, IO = 75 mA to 175 mA 10 mV = ±0.017% Output Ri pple Vin = 12 V, IO = 175 mA 400 mVpp Effi ci ency Vin = 12 V, IO = 175 mA 87.7% Output Ri pple Wi th Opti onal Fi lter Vin = 12 V, IO = 175 mA 40 mVpp Step–Up Converter 170 µH L 8 1 180 S Q Q1 R 7 Rsc 0.22 Vin 12 V Q2 Ipk Osc. 2 CT 1N5819 6 + VCC 100 3 + - Comp. 1.25V Reference Regulator CT 1500 pF 5 4 2.2k Revision 1, May 2002 R2 Vout 47k 28 V / 175 mA 330 R1 + 1.0 µH Vout + CO 100 Optional Filter 4 www.gammamicro.com GM34063 PRELIMINARY 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT Figure 9. External Current Boost Connections for IC Peak Greater than 1.5 A 8 1 S Q Q2 R Q1 7 100 Ipk Oscillator Rsc Vout 2 CT 6 Vin Comparator + 1.25V Reference Regulator - External NPN Switch If the output switch is driven into hard saturation (non – Darlington configuration) at low switch currents (#300 mA) and high driver currents ($30 mA), it may take up to 2.0 µs to come out of saturation. This condition will shorten the off time at frequencies $30 kHz, and is magnified at high temperatures. This condition does not occure with a Darlington configuration, since the output switch cannot saturate. If a non–Darlington configuration is used, the following output drive condition is recommended. 8 1 S Q Q2 Q1 R 7 Vin 100 Ipk Oscillator Rsc Vout 2 CT 6 Comparator + - R 6 0 for const. Vin 1.25V Reference Regulator External NPN Saturated Switch Revision 1, May 2002 5 www.gammamicro.com GM34063 PRELIMINARY 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT Test Conditions Results Line Regulation Vin = 15 V to 25 V, IO = 500 mA 12 mV = ±0.12% Load Regulation Vin = 25 V, IO = 75 mA to 500 mA 3.0 mV = ±0.03% Output Ripple Vin = 25 V, IO = 500 mA Short Circuit Current Vin = 25 V, RL = 0.1 S 1.1 A Efficiency Vin = 25 V, IO = 500 mA 83.7% Output Ripple With Optional Filter Vin = 25 V, IO = 500 mA 40 mVpp 120 mVpp Step – Down Converter 8 1 S Q Q1 R 7 Rsc 0.33 Vin 25 V Q2 Ipk Osc. 2 CT 6 + VCC 100 + - Comp. 220 µH 1N5819 1.25V Reference Regulator 3 5 4 CT 470 pF R2 R1 1.2k Revision 1, May 2002 Vout 3.6k 470 + 1.0 µH Vout 5.0 V / 500 mA 100 CO Optional Filter 6 www.gammamicro.com GM34063 PRELIMINARY 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT Figure 11. External Current Boost Connections for IC Peak Greater than 1.5 A 1 8 S Q Q2 R 7 Q1 2 Ipk Oscillator Rsc CT Vout 6 Vin Comparator + 1.25V Reference Regulator - External NPN Switch 1 8 S Q Q2 7 Ipk Oscillator Rsc Vin 6 Vout Q1 R 2 CT Comparator + - 1.25V Reference Regulator External PNP Saturated Switch Revision 1, May 2002 7 www.gammamicro.com GM34063 PRELIMINARY 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT Test Conditions Results Line Regulation Vin = 4.5 V to 6.0 V, IO = 100 mA 3.0 mV = ±0.012% Load Regulation Vin = 5.0 V, IO = 10 mA to 100 mA 0.022 V = ±0.09% Output Ripple Vin = 5.0 V, IO = 100 mA Short Circuit Current Vin = 5.0 V, RL = 0.1 S Efficiency Vin = 5.0 V, IO = 100 mA 62.2% Output Ripple With Optional Filter Vin = 5.0 V, IO = 100 mA 70 mVpp 500 mVpp 910 mA Voltage Inverting Converter 8 1 S Q 2 Rsc 0.24 Ipk Osc. 6 + Q1 R 7 Vin 4.5 V to 6V Q2 VCC 100 88 µH CT L 1N5819 + - Comp. 1.25V Reference Regulator 3 + 1500 pF 5 4 R1 R2 8.2k Revision 1, May 2002 Vout 953 1000 µf CO + 1.0 µH Vout -12 V / 100 mA + 100 Optional Filter 8 www.gammamicro.com GM34063 PRELIMINARY 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT Figure 13. External Current Boost Connections for IC Peak Greater than 1.5 A 1 8 S Q Q2 Q1 R 7 2 Rsc Ipk Oscillator Vout CT 6 Vin Comparator + 1.25V Reference Regulator - External NPN Switch 1 8 S Q Q2 Vout Q1 R 7 Rsc Vin 2 Ipk Oscillator 6 CT Comparator + - 1.25V Reference Regulator External PNP Saturated Switch Revision 1, May 2002 9 www.gammamicro.com GM34063 PRELIMINARY 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT DESIGN FORMULAS Calculation Step-Up V Step-Dow n +V -V V out F in(min) __________________________ ton/toff +V Voltage-Inverting |V | + V out F __________________________ Vin(min) - Vsat out F __________________________ Vin(min) - Vsat - Vout V i n - V sa t 1 f 1 f 1 f (ton + toff) t +t t +t t +t on off _______________ on off _______________ on off _______________ toff _to_n_ +1 toff _to_n_ +1 toff _to_n_ +1 toff ton (ton + toff) - toff (ton + toff) - toff (ton + toff) - toff CT 4.0 x 10 4.0 x 10 4.0 x 10 -5 ton t 2lout(max) _o_n_ + 1 toff Ipk(switch) ( Rsc ) (Vin(min) - Vsat) (___I_______) pk(switch) CO 9 ton(max) ton (_V_in_ - Vsa_ - Vou_ ) (mi_ n) ___ t __ t _ Ipk(switch) I t I ) ton ( 0.3/lpk(switch) ( -5 t 2lout(max) _o_n_ + 1 toff 2lout(max) 0.3/lpk(switch) L(min) -5 ton(max) (t + t ) out on _____________________ pk(switch) on off __________________________ Vripple(pp) 8Vripple(pp) ) 0.3/lpk(switch) (Vin(min) - Vsat) (___I_______) pk(switch) 9 ton(max) I t out on _____________________ Vripple(pp) Vsat = Saturation voltage of the output switch. VF = Forward voltage drop of the output rectifier. Vin – Nominal input voltage. Vout – Desired output voltage, Iout – Desired output current. fmin – Minimum desired output switching frequency at the selected values of Vin and IO. Vripple(pp) – Desired peak–to–peak 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. ORDERING INFORMATION . GM34063 Revision 1, May 2002 PACKAGE PART No. SOP-8 GM34063S8 DIP-8 GM34063D8 10 www.gammamicro.com