UCC28231

适用于总线转换器的高级 PWM 控制器，具有 3.3V 精密电压基准

The UCC28230, 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 asthe 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:

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Start-up frequency control circuit allowing small output inductor andthe ability to start with large intermediate bus capacitor.

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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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Programmable, Load Depended Off Time Control

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Frequency Controlled Start Up Allows Small Output Inductor, Low Ripple and Constant Current Start with Large Output Capacitor

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Two 0.2-A Push-Pull Outputs Provide Matched Control Signals D to External Drivers

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Two Additional 1- D Outputs for Optimal Use of Self-Driven or Control Driven Synchronous Rectifiers

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Unregulated, Fixed Volt-Second or Fixed Frequency Modes set by User

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Two, 1.5% Overall Accuracy Reference Voltage Options: 5-V for UCC28230 and 3.3-V for UCC28231

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Resistor Programmable Switching Frequency up to 1 MHz

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Cycle-by-Cycle Current Limit Allows Parallel Operation with Droop Based Current Sharing

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Single External Capacitor sets Soft-Start and Over Current Hiccup Mode Parameters with Restart

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Severe Short Circuit Hiccup with Restart or Latch Off Protection Option by External Resistor

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Input Under Voltage Lock Out

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Thermal Shutdown

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Thermally Enhanced 3 mm × 2 mm SON-12 and TSSOP-14 Package Options

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APPLICA ONS

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Intermediate Bus Isolated Converters

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DC-to-DC Transformers