UCC28250_12 Datasheet, PDF (1/53 Pages) Texas Instruments – Advanced PWM Controller With Pre-Bias Operation

UCC28250
www.ti.com
SLUSA29C – APRIL 2010 – REVISED JULY 2011
Advanced PWM Controller With Pre-Bias Operation
Check for Samples: UCC28250
FEATURES
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• Pre-biased 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
• 1-MHz Capable Switching 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 QFN-20
Package and 20-pin TSSOP Package
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
DESCRIPTION
The UCC28250 PWM controller is designed for high
power density applications that may have stringent
pre-biased startup requirements. The UCC28250’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 UCC27200 half bridge drivers and
UCC2732X MOSFET drivers used in conjunction with
the UCC28250 provide a complete power converter
solution.
Externally programmable soft-start, used in
conjunction with an internal pre-biased startup circuit,
allows the controller to gradually reach a steady-state
operating point under all output conditions. The
UCC28250 can be configured for primary or
secondary-side control and either voltage or current
mode control can be implemented.
The oscillator operates at frequencies up to 2 MHz,
and can be synchronized to an external clock. Input
voltage feedforward, cycle-by-cycle current limit, and
a programmable hiccup timer allow the system to
stay within a safe operation range. Input voltage,
output voltage and temperature protection can be
implemented. Dead time between primary-side switch
and secondary-side synchronous rectifiers can be
independently programmed.
Simplified Application Diagram
VIN (36 V ~ 75 V)
UCC28250
OVP OUTA
VIN (36 V ~ 75 V)
UCC27200
HI
HI
V_OUT
RAMP OUTB
LO
LO
RT
SRA
SS
SRB
Isolation
UCC2732x
COMP
GND
Feedback and Isolation
Not Shown: PS, SP, HICC, VDD, EA+, EA-, VREF, EN, ILIM, AND VSENSE
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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 © 2010–2011, Texas Instruments Incorporated