SC531 Datasheet, PDF (1/15 Pages) Semtech Corporation – Triple Low-side FET Driver with Digitally Controlled Current Limit

SC531
Triple Low-side FET Driver with
Digitally Controlled Current Limit
POWER MANAGEMENT
Features
Description
 Dual 2A Source, 4A Sink FET Drivers
 Second Channel Enable
 Independent Drive Supplies
 Auxiliary 2A Source, 4A Sink FET Driver
 Precision Reference Output
 Current Limit Reference Output (Analog) Integrated
Current Sense Blanking (Digital Input)
 Digitally Controlled High Precision Current Limit
 Current Limit Flag
 Current Input ZVS Comparator
 SPI Communications — 25 MHz
 Thermally Enhanced 4x4 (mm) MLPQ-UT-28 Package
 Lead-free, Halogen free, and RoHS/WEEE compliant
Applications
 Digitally Controlled Power Supplies
 Flyback Converter
 Boost Converter
 Forward Converter
 DC-DC and AC-DC Converters With Active Clamp
 PFC Converters With ZVT
 Constant Current Converter
Typical Application Circuit
HVIN
CIN
3.3V
1µF
VCC
ZVS
The SC531 combines three low side drivers with a high
speed digitally programmable current limit and a zero
voltage switching (ZVS) comparator. Two drivers are nor-
mally used to operate the FETs for the power stage. They
can operate separately to drive individual power FETs or
can be combined to drive a single device. A third, auxil-
iary, gate drive is controlled by an independent input and
can be used to drive the FET for an active clamp or ZVT
switching. All three drivers have an independent supply
which allows each drive voltage to be optimized for high
efficiency.
In addition, the SC531 has an SPI interface, 8-bit DAC, and
current limit comparator to provide a high-speed digitally
programmable current limit. This circuitry can be used for
cycle by cycle current limiting or current waveform
shaping. A digital output current limit flag is available for
monitoring by the host controller.
The SC531 also has a current-input ZVS comparator that
can be used to sense changes in high voltage nodes, such
as the power FET drain and inductor node (LX) versus the
power stage supply, (HV_IN in the typical application
circuit).
D1
T1
VOP
15pF
COUT
VON
D2
200W*
SPI
Interface
8-bit
DAC
IN
OE2B
ZVSN
SC531
IN3
ZVSP
1MW
1MW
PVDD1
9V
A0
1µF
OUT1
DIN
PGND1
CSB
PVDD2
9V
CLK
1µF
OUT2
DAC
PGND2
VREFH
PVDD3
9V
1µF
VREF
OUT3
47nF
VREFL
PGND3
1kW
2.49W
180pF*
C3
Q1
Q2
Q3
*optional
BLANKB
CLF
GND CSENSE
Rev 2.0
© Semtech Corporation