POWER MANAGEMENT
1
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SC2602/SC2602A
Synchronous Voltage Mode Controller
for Distributed Power Supply Applications
Features
Applications
Revision: November 18, 2004
Typical Application Circuit
Description
Synchronous operation for high efficiency (95%)
R
DS(ON)
current sensing
On-chip power good and OVP functions
Small size with minimum external components
Soft Start
Enable function
Microprocessor core supply
Low cost synchronous applications
Voltage Regulator Modules (VRM)
DDR termination supplies
Networking power supplies
Sequenced power supplies
The SC2602 and SC2602A are low-cost, full featured,
synchronous voltage-mode controllers designed for use
in single ended power supply applications where efficiency
is of primary concern. Synchronous operation allows for
the elimination of heat sinks in many applications. The
SC2602s are ideal for implementing DC/DC converters
needed to power advanced microprocessors in low cost
systems, or in distributed power applications where effi-
ciency is important. Internal level-shift, high-side drive
circuitry, and preset shoot-thru control, allows the use of
inexpensive N-channel power switches.
SC2602s features include temperature compensated
voltage reference, triangle wave oscillator and current
sense comparator circuitry. Power good signaling, shut-
down, and over voltage protection are also provided.
The SC2602 operates at a fixed 200kHz and the
SC2602A at 500kHz, providing a choice for optimum
compromise between efficiency, external component size,
and cost.
Two SC2602s can be used together to sequence power up
of telecom systems. The power good of the first SC2602
connected to the enable of the second SC2602 makes
this possible.
Typical Distributed Power Supply
Figure 1.
VCC
1
PWRGD
2
OVP
3
OCS ET
4
PHASE
5
DRVH
6
PGND
7
DRVL
8
BSTL
9
BSTH
10
SENSE
11
SS/SHDN
13
GND
14
U1
SC2602
Q1
STP40NE
Q2
STP40NE
R5
3.9
L1
2uH
C9
180/4V
C10
180/4V
C11
180/4V
C12
180/4V
C7
680/6.3V
C6
680/6.3V
R1
1k
R3
1k
C2
0.1
C3
0.1
C1
0.1
R2
PWRGD
OVP
SHDN
+
_
+
_
Vin
5V
Vout=2.5
*
R7
127
R8
124*
NOTE:
*) Vout = 1.265 x (1+R8/R7)
+5V
D1
MBR0520
R6
2.2
C4
1.0
C5
10.0
C8
680/6.3V
R4
10
+12V
C13
180/4V
0.1
COMP
12
4.99K
820pF
