UCC28230_15 Datasheet, PDF (1/50 Pages) Texas Instruments – Advanced PWM Controller for Bus Converters

UCC28230
UCC28231
www.ti.com ................................................................................................................................................... SLUS814A – FEBRUARY 2008 – REVISED JUNE 2008
Advanced PWM Controller for Bus Converters
FEATURES
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• Programmable, Load Depended Off Time
Control
• Frequency Controlled Start Up Allows Small
Output Inductor, Low Ripple and Constant
Current Start with Large Output Capacitor
• Two 0.2-A Push-Pull Outputs Provide Matched
Control Signals D to External Drivers
• Two Additional 1- D Outputs for Optimal Use
of Self-Driven or Control Driven Synchronous
Rectifiers
• Unregulated, Fixed Volt-Second or Fixed
Frequency Modes set by User
• Two, 1.5% Overall Accuracy Reference Voltage
Options: 5-V for UCC28230 and 3.3-V for
UCC28231
• Resistor Programmable Switching Frequency
up to 1 MHz
• Cycle-by-Cycle Current Limit Allows Parallel
Operation with Droop Based Current Sharing
• Single External Capacitor sets Soft-Start and
Over Current Hiccup Mode Parameters with
Restart
• Severe Short Circuit Hiccup with Restart or
Latch Off Protection Option by External
Resistor
• Input Under Voltage Lock Out
• Thermal Shutdown
• Thermally Enhanced 3 mm × 2 mm SON-12
and TSSOP-14 Package Options
APPLICATIONS
• Intermediate Bus Isolated Converters
• DC-to-DC Transformers
DESCRIPTION
The UCC28230, UCC28231 PWM bus controllers are
optimized for use in high efficiency, high power
density, unregulated intermediate bus converters.
Topologies include push-pull, half-bridge and
full-bridge. External drivers, such as the UCC27200
120-V high-side/low-side drivers, can be used with
this controller.
Low cost, small size and highly efficient solutions are
provided by innovations such as:
• Start-up frequency control circuit allowing small
output inductor and the ability to start with large
intermediate bus capacitor.
• Load depended off-time control set by user.
Additional 1-D control outputs can be used for
primary winding clamping in self-driven output
synchronous rectifier applications or as drive signals
for the control-driven synchronous rectifier.
Cycle-by-cycle current limit prevents overstresses of
converter. If the over current condition causes less
than 80% duty cycle at the output, then after a
programmed time the controller proceeds into
periodical shutdown and restart hiccup mode.
The UCC28230 provides 5 V, and the UCC28231
provides 3.3-V precision reference voltages with 1.5%
overall accuracy and 10-mA output current. This
reference voltage can be used to supply
housekeeping circuit and/or microcontroller. The
precision reference voltage can also be used for
accurate setting of system parameters.
Other features include under-voltage lockout, thermal
shut down, programmable soft start, over-current
hiccup mode and short circuit protection with internal
restart by default that can be set into latch-off mode
by an external resistor.
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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 © 2008, Texas Instruments Incorporated