SC2677 Datasheet, PDF (1/9 Pages) Semtech Corporation – Dual Synchronous Voltage Mode Controller with Current Sharing Circuitry

SC2677
Dual Synchronous Voltage Mode
Controller with Current Sharing Circuitry
POWER MANAGEMENT
Description
Features
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_CC. The phasing between the two switchers is ad-
justable to minimize the input and output ripple.
Simplified Application Schematic
‹ 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
Two Phase, Current Sharing Controller
‹ Flexible, same or separate V_IN
‹ Programmable current sharing
‹ Thermal distribution via multi-phase output
Applications
‹ Graphics cards
‹ Peripheral add-in card
‹ Dual-Phase power supply
‹ Power supplies requiring two outputs
PWRGD
EN ABLE
+12V
+5V
C1
R1
C5
R4
R7
U1
M1
SC2677
L1
1
2
M2
C2
C3
1uF
R2
R3
C4
R5
R6
0R0
C6
R8
Vout 1
C7
R 10
+3. 3V
C9
C8
+12V
M3
R9
R11
L2
1
2
M4
Vout 2
C 10
Revision: NOV. 15, 2004
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