POWER MANAGEMENT

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SC2677

Dual Synchronous Voltage Mode

Controller with Current Sharing Circuitry

Description

Features

Applications

Revision: NOV. 15, 2004

The SC2677 is a versatile 2 phase, synchronous, volt-

age mode PWM controller that may be used in two dis-

tinct ways. First, the SC2677 is ideal for applications

where point of use output power exceeds any single in-

put power budget. Alternatively, the SC2677 can be used

as a dual switcher. The SC2677 features a temperature

compensated voltage reference, an under voltage lock-

out over current protection and internal level-shifted, high-

side drive circuitry.

In current sharing configuration, the SC2677 can pro-

duce a single output voltage from two separate voltage

sources (which can be different voltage levels) while

maintaining current sharing between the channels. Cur-

rent sharing is programmable to allow loading each input

supply as required by the application.

In dual switcher configuration, two feedback paths are

provided for independent control of the separate outputs.

The device will provide a regulated output from flexibly

configured inputs (3.3V, 5V, 12V), provided 5V is present

for V

justable to minimize the input and output ripple.

300kHz to 1MHz externally programmable

frequency operation

Soft Start and Enable function

Power Good output provided

Under voltage short circuit protection

Phase-shifted switchers minimize ripple

High efficiency operation, >90%

Programmable output(s) as low as 0.5V

Industrial temperature range

TSSOP-20 package

Bias voltage as low as 4.5V

Adjustable phase shift between channels

TTTTTw

w

w

w

wo Phase, Current Sharing Controller

o Phase, Current Sharing Controller

o Phase, Current Sharing Controller

o Phase, Current Sharing Controller

o Phase, Current Sharing Controller

Flexible, same or separate V

IN

Programmable current sharing

Thermal distribution via multi-phase output

Graphics cards

Peripheral add-in card

Dual-Phase power supply

Power supplies requiring two outputs

Simplified Application Schematic

C7

M4

L1

1

2

+5V

L2

1

2

R2

C1

PWRGD

R7

C6

C5

R1

C3

1uF

+3.3V

C9

R6

0R0

R10

R8

R4

U1

SC2677

+12V

C4

R9

M2

Vout1

M1

R5

R11

+12V

C8

C10

ENABLE

Vout2

R3

C2

M3