UCC28056CDBVT datasheet(24/55 Pages) TI2

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UCC28056

SLUSD37E – OCTOBER 2017 – REVISED NOVEMBER 2019

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Feature Description (continued)

8.3.5.5 Line Under-Voltage or Brown-In

The input rectifier and capacitor form an analog peak detector that accumulates the peak Line voltage applied to

the input. This peak Line voltage appears across the Boost MOSFET. The controller observes peak Line voltage

via the external divider network attached to the ZCD/CS pin. The Line voltage start comparator does not allow

the controller to exit the Stopb state until the ZCD/CS pin voltage rises above the VZCBoRise threshold. This

behavior ensures that switching operation does not start until the Line voltage is high enough (85 VRMS) to deliver

full output power. During switching operation, the controller continues to operate regardless of the Line voltage,

until a fault causes it to enter a Stopb state.

8.3.6 High-Current Driver

An integrated, high-current driver allows the UCC28056 controller to drive the power MOSFET switch directly.

The controller limits the voltage applied to the DRV pin to VDRHigh. This limit enables a high VCC supply rail to

drive the controller without exceeding the VGS voltage rating of the power MOSFET. This limit also reduces

power dissipation in the internal gate driver when the controller operates from a VCC rail that is higher than

VDRHigh.

The integrated driver is protected against temporary short circuit of the DRV and GND pins.

UCC28056CDBVT 데이터시트(PDF) 24 Page - Texas Instruments