SC2677B Dual Synchronous Voltage Mode Controller with Current Sharing Circuitry POWER MANAGEMENT Features Description The SC2677B is a versatile 2 phase, synchronous, voltage 300kHz to 1MHz externally programmable mode PWM controller that can be used in two distinct ways. frequency operation First, the SC2677B is ideal for applications where point of Soft Start and Enable function use output power exceeds any single input power budget. Power Good output provided Alternatively, the SC2677B can be configured as a dual Cycle-by-cycle peak current limit switcher. The SC2677B features a precise temperature Latch off for over current protection compensated voltage reference, cycle-by-cycle peak cur- Phase-shifted switchers minimize ripple rent limit, under voltage lockout over current protection, High efficiency operation, >90% and internal level-shifted high-side gate drive circuitry. Programmable output(s) as low as 0.5V Industrial temperature range In current sharing configuration, the SC2677B can pro- TSSOP-24 package duce a single output voltage from two separate input volt- TSSOP-24 EDP package age sources (which can be different in voltage levels) while Bias voltage as low as 4.5V maintaining current sharing between the two channels. Adjustable phase shift between channels Current sharing is programmable to allow each input sup- ply to be loaded differently per application requirements. Two Phase, Current Sharing Controller Flexible, same or separate V IN In dual switcher configuration, two feedback paths are pro- Programmable current sharing vided for independent control of the separate outputs. The Thermal distribution via multi-phase output device will provide a regulated output from flexibly config- ured inputs, such as 3.3V, 5V, 12V etc. The phasing be- Applications tween the two switchers is adjustable to minimize the in- Graphics cards put and output ripple. Peripheral add-in card Dual-Phase power supply Power supplies requiring two outputs Typical Application Schematic D2 CS1- R51 CS1+ C63 D1 C6 R50 L1 M1 1 2 Vout1 C4 M3 R5 C19 C23 R8 PWRGD ENABLE CS1+ CS1- C28 R13 C26 C25 R10 R14 Vin U1 SC2677B R19 C33 R21 R20 CS2+ CS2- C36 CS2- R49 C39 C38 CS2+ C62 R18 R48 L2 1 2 Vout2 M5 C43 M7 C57 D3 C59 D4 Dual Independent outputs Revision: Dec. 04, 2009 1 www.semtech.com 1 24 CS2+ CS1+ 2 23 CS2- CS1- 3 22 VREF GND 4 21 FREQ PWRGD 5 20 VCC SS/ENA 6 19 +IN2 PHASING 7 18 -IN2 -IN1 8 17 COMP2 COMP1 9 16 BST2 BST1 10 15 DH2 DH1 11 14 DL2 DL1 12 13 PGND BSTCSC2677B Dual Synchronous Voltage Mode Controller with Current Sharing Circuitry POWER MANAGEMENT Typical Application Schematic D2 CS1- Vin3 R51 CS1+ C63 D1 C6 R50 L1 M1 VP1 1 2 Vin1 Vout C4 M3 C19 R5 C23 R8 PWRGD ENABLE CS1+ CS1- C28 R13 C26 C25 R10 R14 U1 SC2677B R19 C33 R21 CS2+ CS2- C35 C36 VOUT C37 VOUT R26 R22 Vin3 R24 C38 C39 VP2 VP1 CS2- R49 CS2+ D C62 R48 L2 VP2 1 2 Vin2 M5 C43 C59 M7 C57 D3 D4 Vin3 Dual Input, Single output, Current share Mode D2 CS1- R51 CS1+ C63 D1 C6 R50 L1 M1 VP1 1 2 Vout C4 M3 C19 R5 C23 R8 PWRGD ENABLE CS1+ CS1- C28 R13 C26 C25 R10 R14 Vin U1 SC2677B R19 C33 R21 CS2+ CS2- C35 C36 VOUT C37 VOUT R26 R22 R24 C38 C39 VP2 VP1 CS2- R49 CS2+ D C62 R48 L2 VP2 1 2 M5 C43 C59 M7 C57 D3 D4 Single Input/output, Current share Mode 2 www.semtech.com 1 24 CS2+ CS1+ 2 23 CS2- CS1- 3 22 1 24 CS2+ CS1+ VREF GND 2 23 4 21 CS2- CS1- FREQ PWRGD 3 22 5 20 VREF GND VCC SS/ENA 4 21 6 19 FREQ PWRGD +IN2 PHASING 5 20 7 18 VCC SS/ENA -IN1 -IN2 6 19 +IN2 PHASING 8 17 COMP2 COMP1 7 18 -IN2 -IN1 9 16 BST2 BST1 8 17 COMP2 COMP1 10 15 DH2 DH1 9 16 BST2 BST1 11 14 DL2 DL1 10 15 DH2 DH1 12 13 PGND BSTC 11 14 DL2 DL1 12 13 PGND BSTC