POWER MANAGEMENT
1
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SC2677B
Dual Synchronous Voltage Mode
Controller with Current Sharing Circuitry
Features
Revision: Dec. 04, 2009
The SC2677B is a versatile 2 phase, synchronous, voltage
mode PWM controller that can be used in two distinct ways.
First, the SC2677B is ideal for applications where point of
use output power exceeds any single input power budget.
Alternatively, the SC2677B can be configured as a dual
switcher. The SC2677B features a precise temperature
compensated voltage reference, cycle-by-cycle peak cur-
rent limit, under voltage lockout over current protection,
and internal level-shifted high-side gate drive circuitry.
In current sharing configuration, the SC2677B can pro-
duce a single output voltage from two separate input volt-
age sources (which can be different in voltage levels) while
maintaining current sharing between the two channels.
Current sharing is programmable to allow each input sup-
ply to be loaded differently per application requirements.
In dual switcher configuration, two feedback paths are pro-
vided for independent control of the separate outputs. The
device will provide a regulated output from flexibly config-
ured inputs, such as 3.3V, 5V, 12V etc. The phasing be-
tween the two switchers is adjustable to minimize the in-
put and output ripple.
300kHz to 1MHz externally programmable
frequency operation
Soft Start and Enable function
Power Good output provided
Cycle-by-cycle peak current limit
Latch off for over current protection
Phase-shifted switchers minimize ripple
High efficiency operation, >90%
Programmable output(s) as low as 0.5V
Industrial temperature range
TSSOP-24 package
TSSOP-24 EDP package
Bias voltage as low as 4.5V
Adjustable phase shift between channels
Two 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
CS1+
CS2+
C6
M5
C62
D1
CS1+
R20
C39
R49
R5
C63
M7
PWRGD
Vout2
R48
R21
D3
D2
C4
C25
M3
C38
CS2-
CS2-
R8
L1
1 2
D4
C36
C23
C19
CS1-
L2
1 2
U1 SC2677B
3
4
5
6
7
8
9
10
11
12 13
22
21
20
19
18
17
16
15
14
1
2 23
24
VREF
FREQ
VCC
+I N2
-IN2
COMP2
BST2
DH2
DL2
PGND BSTC
GND
PWRGD
SS/ EN A
PHASI NG
-IN1
COMP1
BST 1
DH1
DL1
CS2+
CS2- CS1-
CS1+
C26
R18
R19
C57
CS1-
R50
Vin
R10
C28
ENABLE
C33
Vout1
CS2+
R13
M1
R14
C43
C59
R51
Dual Independent outputs
Typical Application Schematic
Description
Applications
