UCC28056CDBVT datasheet(5/55 Pages) TI2

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COMP

DRV

GND

VOSNS

ZCD/CS

VCC

UCC28056

www.ti.com

SLUSD37E – OCTOBER 2017 – REVISED NOVEMBER 2019

Product Folder Links: UCC28056

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6 Pin Configuration and Functions

DBV Package

6-Pin SOT-23

Top View

Pin Functions

I/O

DESCRIPTION

NAME

NO.

COMP

I/O

Output of the internal transconductance error amplifier and power demand input. To achieve

compensation of the voltage loop, connect a suitable RC network from this pin to GND. The error

amplifier output is internally limited to VCOClmp. An internal resistor, RCODisch, discharges the external

compensation network when the controller is in its Stopb state or when the Ovp2 comparator is tripped.

Switching stops, and the controller enters a low-power state (BstOffb), when the voltage on the COMP

pin drops below VBSTFall. Switching resumes when the COMP pin voltage exceeds VBSTRise.

DRV

I/O

GATE connection to drive the main power MOSFET. This output is internally limited to VDRHigh. This is

done to reduce power dissipation in the internal driver and allow controller operation from high VCC

voltages. An external resistor connected from DRV to GND adjusts the delay between the Drain

waveform falling below VIn and the DRV rising edge, allowing the turn on transition to be aligned to the

valley minimum accurately over a wide range of idle ring oscillating frequency.

GND

Controller Ground reference pin. Connect to the power stage at the lower terminal of the current sense

resistor, RCS, only.

VCC

Positive supply voltage. Switching operation can start once VCC exceeds VCCStart. Switching operation

ceases if VCC drops below VCCStop for longer than TUVLOBlk.

ZCD/CS

This pin is fed by a potential divider connected across the Drain & Source pins of the power MOSFET

switch. While the DRV pin is high this pin monitors the voltage across the current sense resistor, RCS.

This pin implement over-current protection functions. While the DRV pin in low this pin monitors the Drain

voltage waveform. Input voltage applied to the power stage can be obtained by filtering the Drain

waveform. Input voltage provides Line voltage feed - forward and Line Brown - In features. Drain voltage

waveform is also used to provide ZCD detection, valley synchronization and second level output over -

voltage protection features.

VOSNS

Voltage error amplifier inverting input. The error amplifier non - inverting input connects to internal

reference voltage VOSReg. Error amplifier gain increases with error magnitude to improve transient

response without compromising Line current distortion. Output over-voltage protection is implemented on

this pin. Switching operation halts if the voltage on this pin exceeds VOvp1Rise and resumes when it drops

below VOvp1Fall.

UCC28056CDBVT Datasheet(PDF) 5 Page - Texas Instruments

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