UCC28950
www.ti.com
SLUSA16 – MARCH 2010
Green Phase-Shifted Full-Bridge Controller With Synchronous Rectification
Check for Samples: UCC28950
FEATURES
APPLICATIONS
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Enhanced Wide Range Resonant Zero Voltage
Switching (ZVS) Capability
Direct Synchronous Rectifier (SR) Control
Light-Load Efficiency Management Including
– Burst Mode Operation
– Discontinuous Conduction Mode (DCM),
Dynamic SR On/Off Control with
Programmable Threshold
– Programmable Adaptive Delay
Average or Peak Current Mode Control with
Programmable Slope Compensation and
Voltage Mode Control
Closed Loop Soft Start and Enable Function
Programmable Switching Frequency up to 1
MHz with Bi-Directional Synchronization
(+/-3%) Cycle-by-Cycle Current Limit
Protection with Hiccup Mode Support
150-µA Start-Up Current
VDD Under Voltage Lockout
Wide Temperature Range -40°C to 125°C
Phase-Shifted Full-Bridge Converters
Server, Telecom Power Supplies
Industrial Power Systems
High-Density Power Architectures
Solar Inverters, and Electric Vehicles
DESCRIPTION
The UCC28950 enhanced phase-shifted controller
builds upon Texas Instrument’s industry standard
UCCx895 phase-shifted controller family with
enhancements that offer best in class efficiency in
today’s high performance power systems. The
UCC28950 implements advanced control of the
full-bridge along with active control of the
synchronous rectifier output stage.
The primary-side signals allow programmable delays
to ensure ZVS operation over wide-load current and
input voltage range, while the load current naturally
tunes the secondary-side synchronous rectifiers
switching delays, maximizing overall system
efficiency.
UCC28950 Typical Application
+
CT
CREF
-
R1
UCC28950
R2
1
VREF
GND 24
2
EA+
VDD 23
3
EA-
OUTA 22
CVDD
R3
VSENSE
C1
R5
C2
VDD
4
COMP
OUTB 21
B
CSS
R6 R4 C3
5
SS/EN
OUTC 20
RAB
6
DELAB
OUTD 19
DELCD
OUTE 18
E
8
DELEF
OUTF 17
F
9
TMIN
SYNC 16
QD
C
SYNC
RA(hi)
RT(min)
RT
10 RT
RSUM)
11 RSUM
12 DCM
VREF
VDD
B
VDD
D
VOUT
+
CS 15
ADEL 14
RDCM(hi)
R7
QC
QB
A
D
7
REF
Voltage Current
Sense
VDD
QA
C
RCD
ENABLE
VDD
A
RAEF(hi)
E
UCC27324
QE
UCC27324
QF
F
ADELEF 13
-
RA
RCS
RDCM
RAEF
VSENSE
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2010, Texas Instruments Incorporated
