UCC28251_15 Datasheet, PDF (1/55 Pages) Texas Instruments – UCC28251 Advanced PWM Controller With Prebias Operation

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UCC28251
SLUSBD8E – FEBRUARY 2013 – REVISED DECEMBER 2014
UCC28251 Advanced PWM Controller With Prebias Operation
1 Features
•1 Prebiased Startup
• Synchronous Rectifier Control Outputs with
Programmable Delays (Including Zero Delay
Support)
• Voltage Mode Control with Input Voltage Feed-
Forward or Current Mode Control
• Primary or Secondary-Side Control
• 3.3-V, 1.5% Accurate Reference Output
• Lower Minimum Operating Frequency
• 1% Accurate Cycle-by-Cycle Over Current
Protection with Matched Duty Cycle Outputs
• Programmable Soft-Start and Hiccup Restart
Timer
• Thermally Enhanced 4-mm x 4-mm VQFN-20
Package and 20-pin TSSOP Package
2 Applications
• Half-Bridge, Full-Bridge, Interleaved Forward, and
Push-Pull Isolated Converters
• Telecom and Data-com Power
• Wireless Base Station Power
• Server Power
• Industrial Power Systems
3 Description
The UCC28251 PWM controller is designed for high
power density applications that may have stringent
prebiased startup requirements. The UCC28251’s
integrated synchronous rectifier control outputs target
high efficiency and high performance topologies such
as half-bridge, full-bridge, interleaved forward, and
push-pull. The UCC27210 half bridge drivers and
UCC2752x MOSFET drivers used in conjunction with
the UCC28251 provide a complete power converter
solution.
The UCC28251 is a functional variant of the
UCC28250 PWM Controller. While the same basic
functionality of the UCC28250 is largely maintained,
the UCC28251 is designed to enhance performance
in both offline, 400-V input DC-to-DC applications and
48-V input full-bridge or half-bridge applications.
Device Information⁽¹⁾
PART NUMBER PACKAGE
BODY SIZE (NOM)
UCC28251
TSSOP (20)
VQFN (20)
6.50 mm × 4.40 mm
4.00 mm × 4.00 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Simple Application Diagram (400-V_IN DC-to-DC
Converter)
Secondary
UCC28251
OUTA
VREF
OUTB
RAMP
RT
SRA
SS
SRB
VSENSE
FB
GND
Isolation
Primary
400 V
700-V Driver
HI
HO
LI
LO
Secondary
UCC 2752 x
Secondary
Not Shown : PS, SP, HICC, VDD , EA+, EN AND ILIM
VOUT
Simple Application Diagram (48-V_IN DC-to-DC
Converter)
VIN (36 V ~ 48 V)
UCC28251
OVP OUTA
VIN (36 V ~ 48 V)
UCC27210A
HI
HI
VOUT
RAMP OUTB
LO
LO
RT
SRA
SS
SRB
Isolation
UCC272x
COMP
GND
Feedback and Isolation
Not Shown : PS, SP, HICC, VDD, EA+, EA-, VREF , EN, ILIM, AND VSENSE
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.