SRK2000DTR Datasheet, PDF (1/17 Pages) STMicroelectronics – Synchronous rectifier smart driver for LLC resonant converters

SRK2000
Synchronous rectifier smart driver for LLC resonant converters
Features
■ Secondary-side synchronous rectifier
controller optimized for LLC resonant
converters
■ Protection against current reversal
■ Safe management of load transient, light load
and startup condition
■ Intelligent automatic sleep-mode at light load
■ Dual gate driver for N-channel MOSFETs with
1 A source and 3.5 A sink drive current
■ Operating voltage range 4.5 to 32 V
■ Programmable UVLO with hysteresis
■ 250 µA quiescent consumption
■ Operating frequency up to 500 kHz
■ SO8 package
Applications
■ All-in-one PC
■ High-power AC-DC adapters
■ 80+/85+ compliant ATX SMPS
■ 90+/92+ compliant server SMPS
■ Industrial SMPS
Description
SO-8
corresponding half-winding starts conducting and
switched off as its current goes to zero. A unique
feature of this IC is its intelligent automatic sleep-
mode. It allows the detection of a low-power
operating condition for the converter and puts the
IC into a low consumption sleep-mode where gate
driving is stopped and quiescent consumption is
reduced. In this way, converter efficiency
improves at light load, where synchronous
rectification is no longer beneficial. The IC
automatically exits sleep-mode and restarts
switching as it recognizes that the load for the
converter has increased.
A noticeable feature is the very low external
component count required.
Figure 1. Internal block diagram
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The SRK2000 smart driver implements a control
scheme specific to secondary-side synchronous
rectification in LLC resonant converters that use a
transformer with center-tap secondary winding for
full-wave rectification.
It provides two high-current gate-drive outputs,
each capable of driving one or more N-channel
Power MOSFETs. Each gate driver is controlled
separately and an interlocking logic circuit
prevents the two synchronous rectifier MOSFETs
from conducting simultaneously.
The control scheme in this IC allows for each
synchronous rectifier to be switched on as the
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Table 1. Device summary
Order code
Package
SRK2000D
SRK2000DTR
SO-8
Packing
Tube
Tape and reel
February 2012
Doc ID 17811 Rev 2
1/17
www.st.com
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