SS9175CS-6

SS9175/6 Dual Synchronous DC/DC Controllers With Current Sharing Circuitry FEATURES Two sets of integrated MOSFET drivers Fixed operating frequency of 300, 600 or 1000kHz Dual-phase current-sharing controller to minimize ripple and improve transient response Wide input supply range: 4.5V to 16V Programmable output as low as 0.8v Internal error amplifier reference voltage of 0.7V +/- 1% Programmable over-current protection (OCP) with 50% fold-back Over-voltage protection (OVP) Soft-start Remote ON/OFF control High voltage pin up to 30V for bootstrap voltage Power-good output signal provided Current-sharing balance within +/-5% matching (SS9175CS/SS9176CS) Two independent PWM controllers (SS9175) Packaged in SO-20 (9175/CS) or SO-16 (9176CS) DESCRIPTION The SS9175/6 series are dual-phase synchronous DC/ DC PW M cont rol l ers f or power s u p p l i e s requiring a single high-current output, or two independent outputs with high conversion efficiency. They integrate two sets of internal MOSFET drivers consisting of high-side and low side driving circuits. The internal temperature-independent reference voltage is trimmed to 0.7V +/- 1%, and is connected to the error amplifier’s positive terminal for voltage feedback regulation. The over-current protection (OCP) level, with 50% fold-back, can be programmed by an external resistor. The over-voltage protection (OVP) point is fixed at 25% higher above 0.7V. The soft-start circuit ensures the duty cycle of the PWM output can be gradually and smoothly increased from zero to its desired value. The controllers can be remotely turned ON or OFF to enter into either active or standby mode, respectively. The SS9175/6 series provides three different options: The SS9175 is a 20-pin version that is designed for two independent outputs without current sharing capability. The SS9175CS is a 20-pin version designed for current sharing applications. The SS9176CS is a 16-pin version for current sharing applications. APPLICATIONS n n n n CPU and DSP Vcore Power Supply Graphic cards Telecomm and datacomm POL boards Power supplies requiring two independent outputs TYPICAL APPLICATION CIRCUIT PWRG 1.4v 5V 12V 2.2pF 1uF 1k 7.5uH PWRG IN1 COM VCC CL1+ CL1 BST1 DH1 DL1 PGND GND IN2 COM SS/ENB CL2+ CL2 BST2 DH2 DL2 BSTC 1k 1uF 7.5uH 50k 10uF 450uF 50k 0.22uF Rev.2.02 12/29/2003 PRELIMINARY www.SiliconStandard.com 1 of 12 SS9175/6 ORDERING INFORMATION SS917x xx-xx xx Packing: TR tape and reel: TB tubes Fixed operating frequency: 3/6/10 for 300/600/1000kHz Configuration: CS = current sharing; blank = independent outputs (9175 only) Part/package type: 9175 is in SO-20; 9176 is in SO-16 Examples: SS9176CS-10TR SS9176 with current-sharing outputs, 1000kHz in SO-16 on tape and reel SS9175-6TR SS9175 with independent outputs, 600kHz in SO-20 on tape and reel MARKING INFORMATION 20 16 SS9175UU-H XXXXXXXYYWWV SS9176CS-H XXXXXXXYYWWV 1 UU: = SS9175 UU: CS = SS9175CS H : 3, 6 or 10 XXXXXXX: Wafer Lot YY: Year; WW: Week V: Assembly Location 1 H : 3, 6 or 10 XXXXXXX: Wafer Lot YY: Year; WW: Week V: Assembly Location Rev.2.02 12/29/2003 PRELIMINARY www.SiliconStandard.com 2 of 12 SS9175/6 ABSOLUTE MAXIMUM RATINGS Symbol Vcc PGND VBST RT j-a TJ TA Tstg Parameter Supply voltage, VCC to GND PGND to GND BST to PGND Thermal resistance, Junction-air Operating junction temperature Operating ambient temperature Storage temperature range ESD Capability, HBM model ESD Capability, Machine model Test Condition Low impedance source Value 20 ± 0.7 30 90 -40 to +125 -30 to +85 -65 to +150 2.0 200 Unit V V V °C/W °C °C °C kV V - RECOMMENDED OPERATING CONDITIONS Symbol VCC TA Parameter Supply voltage Operating ambient temperature Min. 4.5 0 Max. 16 70 Unit V °C ELECTRICAL CHARACTERISTICS (VCC=12V, Ta=25°C) Oscillator Section Symbol Fosc-3 Fosc-6 Fosc-10 fdv fdt DC Max Parameter Oscillator frequency -3 version Oscillator frequency -6 version Oscillator frequency -10 version Frequency change with VCC Frequency change with temp. Maximum duty cycle Test Condition Ta=25°C Ta=25°C Ta=25°C VCC=4.5 to 16V Ta=0 to 70°C Min. 270 550 920 85 Typ. 300 600 1000 0.2 0.02 95 Max. 330 650 1080 - Unit KHz KHz KHz % %/°C % Error Amplifier Section Symbol Vref Avol BW PSRR Isource Isink VH COMP VL COMP Parameter Internal reference voltage Open-loop voltage gain Unity gain bandwidth Power supply rejection ratio Output source current Output sink current Output voltage Output voltage Test Condition Ta=25°C - Min. 0.693 45 0.7 50 Typ. 0.7 55 1.2 - Max. 0.707 - Unit V dB MHz dB mA mA V mV Output Section Symbol Tr Tf IDH, CH IDH, DIS Parameter Rising time Falling time High side source current High side sink current Test Condition Ta=25°C, CL=10nF Ta=25°C, CL=10nF Min. 1 1 Typ. 20 20 Max. 50 50 Unit nS nS A A Total Operating Current Section Symbol ICC OP ICC SBY Parameter Operating supply current Standby current (disabled) Test Condition VCC=12V, OUTPUT=1000pF Min. - Typ. 5.0 0.5 Max. Unit mA mA Rev.2.02 12/29/2003 PRELIMINARY www.SiliconStandard.com 3 of 12 SS9175/6 BLOCK DIAGRAMS SS9175 VCC LDO VDD POR D C R Q LDO BSTC BST1 CL1+ DH1 COMP1 OCP IN1 OSC PWRGD BG CL1DL1 BST2 CL2+ PWRGD OSC IN2 COMP2 OSC180 OCP DH2 CL2DL2 D Q R GND GND 25u C PGND SS/ENB SS9175CS VCC LDO VDD POR D C R Q LDO BSTC BST1 CL1+ DH1 COMP1 IN1 OSC PWRGD BG CS OCP CL1 DL1 BST2 CL2+ PWRGD OSC OSC180 CS OCP DH2 CL2DL2 D Q R GND GND 25u C PGND SS/ENB Rev.2.02 12/29/2003 PRELIMINARY www.SiliconStandard.com 4 of 12 SS9175/6 BLOCK DIAGRAMS (cont.) SS9176CS VCC LDO VDD POR D C R Q LDO BSTC BST1 CL+ DH1 COMP IN OSC BG CS OCP CL1 DL1 BST1 OSC PWRGD PWRGD OSC180 CS OCP DH2 CL2DL2 GND GND 25u D C R Q PGND SS/ENB Rev.2.02 12/29/2003 PRELIMINARY www.SiliconStandard.com 5 of 12 SS9175/6 PIN DESCRIPTIONS Pin No. 1 (1) 2 (2) 3 (3) 4 (4) 5 6 7 (5) 8 (6) 9 (7) 10 (8) 11 (9) 12 (10) 13 (11) 14 (12) 15 (13) 16 (14) 17 (15) 18 19 20 (16) Symbol PWRGD IN1 COMP1 VCC CL1+ CL1BST1 DH1 DL1 PGND BSTC DL2 DH2 BST2 CL2CL2+ SS/EN COMP2 [NC] IN2 [NC] GND Function Power-good Feedback Compensation Power Supply Over-current Over-current Boost supply High-side drive Low-side drive Driver ground Buffered supply Low-side drive High-side drive Boost supply Over-current Over-current Soft-start/Enable Compensation Feedback Control ground Description Output of the error amplifier and input to the PWM comparator. It is used for feedback loop compensation. Inverting input of the error amplifier. It is normally connected to the switching power supply output through a resistor divider. Output of the error amplifier and input to the PWM comparator. It is used for feedback loop compensation. Supply voltage input. Over-current adjustment and high-side MOSFET supply voltage sense pin. Connect a resistor from this pin to high-side supply voltage. Over-current sense pin. Supply for high-side driver. Connect to bootstrap circuit. High-side MOSFET gate driver pin. Low-side MOSFET gate driver pin. Driver circuit GND supply. Connect to MOSFET’s GND. Voltage supply for internal low-side driver circuit and for high-side bootstrap circuit’s diode input. Its output is 6V if chip supply voltage VCC > 6.5V. If VCC < 6.5V, then BSTC = VCC. Need a 10uF decoupling capacitor connected to PGND. Low-side MOSFET gate driver pin. High-side MOSFET gate driver pin. Supply for high-side driver. Connect to bootstrap circuit. Over-current sense pin. Over-current adjustment and high-side MOSFET supply voltage sense pin. Connect a resistor from this pin to high-side supply voltage. A 25uA internal current source charges an external capacitor for soft start. Pull down this pin to disable the chip. Output of the error amplifier and input to the PWM comparator. It is used for feedback loop compensation. Inverting input of the error amplifier. It is normally connected to the switching power supply output through a resistor divider. Control circuit GND supply. Note: Inside ( ) is the pin assignment for SS9176CS. Inside [ ] is for SS9175CS. PIN CONFIGURATIONS SS9175 SS9176 PWRGD IN1 COMP1 VCC CL1 CL1+ BST1 DH1 DL1 PGND 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 GND IN2 COMP2 SS/ENB CL2+ CL2BST2 DH2 DL2 BSTC PWRGD IN COMP VCC BST1 DH1 DL1 PGND 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 GND SS/ENB CL+ CL2BST2 DH2 DL2 BSTC Rev.2.02 12/29/2003 PRELIMINARY www.SiliconStandard.com 6 of 12 SS9175/6 APPLICATION INFORMATION OPERATION Over-current protection The over-current protection (OCP) is implemented by adding a resistor from the MOSFET supply voltage to the CL+ pin, which sinks a 100uA current source. An internal comparator senses the voltage difference between CL+ and CL- pin. If the CL- pin voltage is lower than the CL+ pin voltage, meaning there is a larger current flowing through the high-side MOSFET, the comparator will trigger the OCP protection. The OCP function also has a 50% fold-back circuit to limit the MOSFET current within the desired over-current value. The SS9175/6 series controllers integrate two sets of synchronous MOSFET driver circuits with current sharing capability. The following descriptions highlight the advantages of the SS917x designs. Soft-start A 25uA start-up current is provided by the SS/EN pin for the start-up sequence. During this start-up sequence, the SS917x is disabled when the SS/EN pin is less than 1.0V. From 1.0V to 3.0V, PWM output duty cycle is gradually and smoothly increased to its desired value. During this time, the current sharing circuit is disabled for smooth soft start. After 3.0V, the current sharing circuit is enabled and the whole circuit operates normally. Oscillator operation The SS9175/6 series have three versions with different oscillation frequencies. The oscillation frequency is fixed at 300 kHz, 600 kHz or 1 MHz. The voltage amplitude of the internal saw tooth oscillator is from 1.2V to 2.8V. Error amplifier The error amplifier’s inverting input is connected to the IN pin, and the output is connected to the COMP pin. The COMP output is available for external compensation, allowing designers to control the feedback-loop frequency-response. Non-inverting input is not wired out to a pin, but it is internally biased to a fixed 0.7V ± 1% voltage. Output driver The high-side driver uses an external bootstrap circuit to provide the required boost supply voltage. The external bootstrap circuit uses the BSTC output voltage for providing the diode voltage. For the low-side driver, the supply voltage is coming from the BSTC output voltage, which is roughly 6V if VCC is larger than 6.5V.The output stage is designed to ensure zero cross-conduction current. Current Sharing The dual-phase controller has current-sharing capability to match both channels to within 5%. Rev.2.02 12/29/2003 PRELIMINARY www.SiliconStandard.com 7 of 12 SS9175/6 APPLICATION INFORMATION (cont.) REFERENCE CIRCUITS Current sharing application using SS9176CS PWRG 1.4v 12v 1uF 2.2pF 7.5uH PWRGD GND IN1 SS/ENB COMP CL2+ VCC CL2BST1 BST2 DH1 DH2 DL1 DL2 PGND BSTC 1k 1uF 7.5uH 50k 450uF 10uF 50k 0.22uF This current sharing circuit is implemented using the SS9176CS. The dual phase MOSFETs must be supplied from the same supply voltage (in this case, from 12V). They can also be supplied from a 5V supply voltage. As there is only a single output voltage (1.4V in this case), the divided voltage is fed back to the IN pin. The VCC supply voltage can be either 12V or 5V, depending on the convenience of PCB layout, but VCC = 12V is recommended. If VCC > 6.5V, the BSTC output is fixed at 6V. This BSTC voltage is used as the supply voltage for the bootstrap circuit’s diodes input. A 10uF capacitor is recommended for BSTC decoupling. A 1k resistor is connected from CL2+ to the MOSFET’s high-side voltage. This 1k resistor is used to program the OCP level. Rev.2.02 12/29/2003 PRELIMINARY www.SiliconStandard.com 8 of 12 SS9175/6 APPLICATION INFORMATION (cont.) Current sharing application using SS9175CS PWRG 1.4v 5V 12V 2.2pF 1uF 1k 7.5uH PWRGD IN1 COMP1 VCC CL1+ CL1 BST1 DH1 DL1 PGND GND IN2 COMP2 SS/ENB CL2+ CL2BST2 DH2 DL2 BSTC 1k 1uF 7.5uH 10uF 450uF 50k 50k 0.22uF This current-sharing circuit is implemented using SS9175CS. The dual phase MOSFETs c an be supplied from different supply voltages (in this case, from 12V for channel 2, and 5V for channel 1). They can be supplied from the same supply voltage, too. As there is only a single output voltage (1.4V in this case), the divided voltage is fed back to the IN1 pin. The VCC supply voltage can be either 12V or 5V, depending on the convenience of PCB layout, but VCC = 12V is recommended. If VCC > 6.5V, the BSTC output is fixed at 6V. This BSTC voltage is used as the supply voltage for the bootstrap circuit’s diodes input. A 10uF capacitor is recommended for BSTC decoupling. A 1k resistor is connected from CL2+ to the MOSFET’s high-side voltage. This 1k resistor is used to program the OCP level. Rev.2.02 12/29/2003 PRELIMINARY www.SiliconStandard.com 9 of 12 SS9175/6 n APPLICATION INFORMATION (cont.) Two independent voltage outputs using SS9175 2.1v PWRG 5V 12V 2.2pF 1uF 1k 7.5uH 50k 25k 450uF PWRGD IN1 COMP1 VCC CL1+ CL1 BST1 DH1 DL1 PGND GND 2.2pF IN2 COMP2 SS/ENB C L2+ CL2BST2 DH2 DL2 BSTC 1k 1uF 7.5uH 50k 50k 10uF 450uF 0.22uF For independent outputs, this design is implemented using SS9175. The dual-phase MOSFETs can be supplied from different supply voltages (in this case, from 12V for channel 2, and 5V for channel 1). They can be supplied from the same supply voltage, too. As there are two independent output voltages (2.1V and 1.4V in this case), the divided voltages are fed back to their respective IN1 and IN2 pins. The VCC supply voltage can be either 12V or 5V, depending on the convenience of PCB layout, but VCC = 12V is recommended. If VCC > 6.5V, the BSTC output is fixed at 6V. This BSTC voltage is used as the supply voltage for the bootstrap circuit’s diodes input. A 10uF capacitor is recommended for BSTC decoupling. A 1k resistor is connected from CL1+ and CL2+ to the MOSFET’s high-side voltages. This 1k resistor is used to program the OCP level. Rev.2.02 12/29/2003 PRELIMINARY www.SiliconStandard.com 10 of 12 SS9175/6 PHYSICAL DIMENSIONS 20 LEAD SOP (unit: inches) Dimensions: Rev.2.02 12/29/2003 PRELIMINARY www.SiliconStandard.com 11 of 12 SS9175/6 PHYSICAL DIMENSIONS (cont.) 16 LEAD SOP (units: inches) Dimensions: Information furnished by Silicon Standard Corporation is believed to be accurate and reliable. However, Silicon Standard Corporation makes no guarantee or warranty, express or implied, as to the reliability, accuracy, timeliness or completeness of such information and assumes no responsibility for its use, or for infringement of any patent or other intellectual property rights of third parties that may result from its use. Silicon Standard reserves the right to make changes as it deems necessary to any products described herein for any reason, including without limitation enhancement in reliability, functionality or design. No license is granted, whether expressly or by implication, in relation to the use of any products described herein or to the use of any information provided herein, under any patent or other intellectual property rights of Silicon Standard Corporation or any third parties. Rev.2.02 12/29/2003 PRELIMINARY www.SiliconStandard.com 12 of 12