GM34063S8

PRELIMINARY GM34063 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 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. PIN CONNECTIONS Switch Collector Switch Emitter Timing Capacitor GND 1 2 3 4 8 7 6 5 Driver Collector Ipk Sense VCC Comparator Inverting unit (Top View) Applications: CD-ROM Motherboards SMPS Power Supply Battery Chargers SCHEMATIC DIAGRAM Driver Collector 8 S Q Q2 Q1 100 Ipk Oscillator 1 Switch Collector Ipk Sense 7 R 2 3 Switch Emitter CT Timing Capacitor VCC 6 Comparator + Comparator Inverting unit 1.25V Reference Regulator 5 4 GND (Bottom View) * The GM34063 has 51 active transistors on-chip. Revision 1, May 2002 1 www.gammamicro.com PRELIMINARY GM34063 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT Absolute Maximum Ratings Rating Power Supply Voltage Comparator Input Voltage Range Switch Collector Voltage Switch Emitter Voltage (VPin 1 = 40 V) Switch Collector to Emitter Voltage Driver Collector Voltage Driver Collector Current (Note 1) Switch Current Power Dissipation and Thermal Characteristics Plastic Package, P, P1 Suffix TA = 25°C Thermal Resistance SOIC Package, D Suffix TA = 25°C Thermal Resistance Operating Junction Temperature Operating Ambient Temperature Range Storage Temperature Range Symbol V CC VIR VC(switch) VE(switch) VCE(switch) VC(driver) IC(driver) ISW Value 40 –0.3 to +40 40 40 40 40 100 1.5 Unit V dc V dc V dc Vc V dc V dc mA A PD R2JA PD R2JA TJ TA Tstg 1.25 100 625 160 +150 0 to +70 –65 to +150 W °C/W mW °C/W °C °C °C Note 1. Maximum package power dissipation limits must be observed. Revision 1, May 2002 2 www.gammamicro.com PRELIMINARY GM34063 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT ELECTRICAL CHARACTERISTICS (VCC = 5.0 V, TA = Tlow to Thigh unless otherwise specified) Characteristics OSCILLATOR Frequency (VPin 5 = 0 V, CT = 1.0 nF, TA = 25°C) Charge Current (VCC = 5.0 V to 40 V, TA = 25°C) Discharge Current (VCC = 5.0 V to 40 V, TA = 25°C) Discharge to Charge Current Ratio (Pin 7 to VCC, TA = 25°C) Current Limit Sense Voltage (I chg = I dischg, TA = 25°C) OUTPUT SWITCH (Note 2) Saturation Voltage, Darlington Connection ( ISW = 1.0 A, Pins 1, 8 connected) Saturation Voltage (Note 3) (ISW = 1.0 A, RPin 8 = 82 S to VCC, Forced $ .20) DC Current Gain (ISW = 1.0 A, VCE = 5.0 V, TA = 25°C) Collector Off–State Current (VCE = 40 V) COMPARATOR Threshold Voltage TA = 25°C TA = Tlow to Thigh Threshold Voltage Line Regulation (V Input Bias Current (Vin = 0 V) CC Symbol Min Typ Max Unit fosc Ichg Idischg Idischg/Ichg Vipk(sense) 24 24 140 5.2 250 33 35 220 6.5 300 42 42 260 7.5 350 kHz :A :A – mV VCE(sat) VCE(sat) hFE IC(off) – – 50 – 1.0 0.45 75 0.01 1.3 0.7 – 100 V V – :A Vth 1.225 1.210 = 3.0 V to 40 V) Reg line IIB 1.25 1.4 -20 1.275 1.29 5.0 -400 V mV nA 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) ICC 4.0 mA 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 PRELIMINARY GM34063 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT Test Li ne Regulati on Load Regulati on Output Ri pple C onditions Vin = 8.0 V to 16 V, IO = 175 mA Vin = 12 V, IO = 75 mA to 175 mA Vin = 12 V, IO = 175 mA R esults 30 mV = ±0.05% 10 mV = ±0.017% 400 mVpp Effi ci ency Output Ri pple Wi th Opti onal Fi lter Vin = 12 V, IO = 175 mA Vin = 12 V, IO = 175 mA 87.7% 40 mVpp Step–Up Converter 170 µH L 8 180 1 SQ 7 Rsc 0.22 Vin 12 V 6 + Ipk Osc. Q2 Q1 2 R CT 3 1N5819 VCC 100 5 R2 47k 2.2k R1 + - Comp. 1.25V Reference Regulator CT 1500 pF 4 Vout 330 + 28 V / 175 mA 1.0 µH Vout + Optional Filter 100 CO Revision 1, May 2002 4 www.gammamicro.com PRELIMINARY GM34063 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT Figure 9. External Current Boost Connections for IC Peak Greater than 1.5 A 8 1 Vout SQ R 7 Rsc Vin 6 Comparator Ipk Oscillator Q2 Q1 100 2 CT + - 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 Vout SQ R 7 Rsc Vin 6 Comparator Ipk Oscillator Q2 Q1 100 2 CT + - 1.25V Reference Regulator R 6 0 for const. Vin External NPN Saturated Switch Revision 1, May 2002 5 www.gammamicro.com PRELIMINARY GM34063 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT Test Line Regulation Load Regulation Output Ripple Short Circuit Current Efficiency Output Ripple With Optional Filter Conditions Vin = 15 V to 25 V, IO = 500 mA Vin = 25 V, IO = 75 mA to 500 mA Vin = 25 V, IO = 500 mA Vin = 25 V, RL = 0.1 S Vin = 25 V, IO = 500 mA Vin = 25 V, IO = 500 mA Results 12 mV = ±0.12% 3.0 mV = ±0.03% 120 mVpp 1.1 A 83.7% 40 mVpp Step – Down Converter 8 1 SQ 7 Rsc 0.33 Vin 25 V 6 + 100 5 R2 R1 1.2k 3.6k Ipk Osc. Q2 Q1 2 R CT 1N5819 VCC + - 220 µH Comp. 1.25V Reference Regulator 3 4 CT 470 pF Vout 470 + 5.0 V / 500 mA 1.0 µH Vout 100 Optional Filter CO Revision 1, May 2002 6 www.gammamicro.com PRELIMINARY GM34063 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT Figure 11. External Current Boost Connections for IC Peak Greater than 1.5 A 8 1 S 7 Rsc Vin 6 Comparator Ipk Oscillator Q Q2 Q1 2 R CT Vout + - 1.25V Reference Regulator External NPN Switch 8 1 SQ R 7 Rsc Vin 6 Ipk Oscillator Q2 Q1 2 Vout CT Comparator + - 1.25V Reference Regulator External PNP Saturated Switch Revision 1, May 2002 7 www.gammamicro.com PRELIMINARY GM34063 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT Test Line Regulation Load Regulation Output Ripple Short Circuit Current Efficiency Output Ripple With Optional Filter Conditions Vin = 4.5 V to 6.0 V, IO = 100 mA Vin = 5.0 V, IO = 10 mA to 100 mA Vin = 5.0 V, IO = 100 mA Vin = 5.0 V, RL = 0.1 S Vin = 5.0 V, IO = 100 mA Vin = 5.0 V, IO = 100 mA Results 3.0 mV = ±0.012% 0.022 V = ±0.09% 500 mVpp 910 mA 62.2% 70 mVpp Voltage Inverting Converter 8 1 SQ 7 Rsc 0.24 Vin 4.5 V to 6V 6 + 100 5 Ipk Osc. Q2 Q1 2 R CT 88 µH L 1N5819 VCC + - Comp. 1.25V Reference Regulator 3+ 4 1500 pF R1 R2 8.2k 953 1000 µf CO + Vout -12 V / 100 mA 1.0 µH Vout + 100 Optional Filter Revision 1, May 2002 8 www.gammamicro.com PRELIMINARY GM34063 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT Figure 13. External Current Boost Connections for IC Peak Greater than 1.5 A 8 1 S 7 Rsc Vin 6 Comparator Ipk Oscillator Q Q2 Q1 2 R CT Vout + - 1.25V Reference Regulator External NPN Switch 8 1 SQ R 7 Rsc Vin 6 Ipk Oscillator Q2 Q1 2 Vout CT Comparator + - 1.25V Reference Regulator External PNP Saturated Switch Revision 1, May 2002 9 www.gammamicro.com PRELIMINARY GM34063 1.5A DC-to-DC CONVERTER CONTROL CIRCUIT DESIGN FORMULAS Calculation ton/toff V Step-Up out F in(min) __________________________ Step-Dow n out F __________________________ Voltage-Inverting out F __________________________ +V -V V +V |V | + V V i n - V sa t 1 f Vin(min) - Vsat 1 f on off _______________ Vin(min) - Vsat - Vout 1 f on off _______________ (ton + toff) t +t t +t on off _______________ t +t toff t_ _on_ +1 toff (ton + toff) - toff 4.0 x 10 -5 t_ _on_ +1 toff (ton + toff) - toff 4.0 x 10 -5 t_ _on_ +1 toff (ton + toff) - toff 4.0 x 10 -5 ton CT Ipk(switch) Rsc L(min) CO ton ton ton t_ 2lout(max) _on_ + 1 toff ( ) ( 2lout(max) 0.3/lpk(switch) (Vin_i_______u__ __ (m n) - Vsat - Vo t ) t_ 2lout(max) _on_ + 1 toff ( ) 0.3/lpk(switch) 0.3/lpk(switch) (___I_______) pk(switch) (Vin(min) - Vsat) ton(max) Ipk(switch) ) ton(max) (___I_______) pk(switch) (Vin(min) - Vsat) ton(max) 9 out on _____________________ It pk(switch) on off __________________________ I (t + t ) Vripple(pp) 8Vripple(pp) 9 out on _____________________ It 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 PACKAGE . GM34063 SOP-8 DIP-8 PART No. GM34063S8 GM34063D8 Revision 1, May 2002 10 www.gammamicro.com