SC1175 Datasheet, PDF (1/20 Pages) Semtech Corporation – Low Power Dual Synchronous DC/DC Controller With Current Sharing Circuitry

SC1175
Low Power Dual Synchronous DC/DC
Controller With Current Sharing Circuitry
POWER MANAGEMENT
Description
Features
The SC1175 is a versatile 2 phase, synchronous, voltage mode
PWM controller that may be used in two distinct ways. First, the
SC1175 is ideal for applications where point of use output power
exceeds any single input power budget. Alternatively, the SC1175
can be used as a dual switcher. The SC1175 features a tempera-
ture compensated voltage reference, over current protection with
50% fold-back and internal level-shifted, high-side drive circuitry.
In current sharing configuration, the SC1175 can produce a single
output voltage from two separate voltage sources (which can be
different voltage levels) while maintaining current sharing between
the channels. Current 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 two switchers are
180° out of phase to minimize input and output ripple.
Applications
u Graphics cards
u DDR Memory
u Peripheral add-in card
u SSTL Termination
u Dual-Phase power supply
u Power supplies requiring two outputs
u 300kHz fixed frequency operation
u Soft Start and Enable function
u Power Good output provided
u Over current protection with 50% fold-back
u Phase-shifted switchers minimize ripple
u High efficiency operation, >90%
u Programmable output(s) as low as 1.25V
u Industrial temperature range
u SOIC 20 pin package
Two Phase, Current Sharing Controller
u Flexible, same or separate V_IN
u Programmable current sharing
u Combined current limit with fold-back
u 2 phases operating opposed for ripple reduction
u Thermal distribution via multi-phase output
Two Independent PWM Controllers
u Flexible, same or separate V_IN
u Independent control for each channel
u Independent and separate current limit
u 2 phases operating opposed for ripple reduction (if same
V_IN used)
Typical Application Circuit
2 Channels with Current Sharing
Revision 7/31/2000
1
www.semtech.com