BP2831A Ver la hoja de datos (PDF) - Unspecified

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componentes Descripción

Fabricante

BP2831A

Non-isolated Buck Offline LED Driver

Unspecified 

晶丰明源半导体

Internal Block Diagram

VCC

17V

9.0V 14V

BP2831A

Non-isolated Buck Offline LED Driver

DRAIN

VCC

HV

MOSFET

OTP

UVLO

RESET

OCP

OVP

CC &

Logic Control

LED

+

CS

Current

Sense

-

400mV

ROVP

GND

Figure 3. BP2831A Internal Block Diagram

Application Information

The BP2831A is a high performance non-isolated

Buck converter specially designed for LED lighting.

The device integrates a 500V power MOSFET. With

very few external components, the converter

achieves excellent constant current control. And it

does not need auxiliary winding for powering the IC

or voltage sensing, hence the system size and cost is

greatly reduced.

Start Up

After system powered up, the VCC pin capacitor is

charged up by the start up resistor. When the VCC

pin voltage reaches the turn on threshold, the internal

circuits start operating. The BP2831A integrates a

17V zener diode to clamp the VCC voltage. Due to

the ultra-low operating current, the auxiliary winding

is not needed to supply the IC.

Constant Current Control

Cycle by Cycle current sense is adopted in BP2831A,

the CS pin is connected to the current sense

comparator, and the voltage on CS pin is compared

with the internal 400mV reference voltage. The

MOSFET will be switched off when the voltage on

CS pin reaches the threshold. The CS comparator

includes a 350ns leading edge blanking time.

The peak inductor current is given by:

I PK



400

R CS

(mA)

Where, RCS is the current sense resistor value.

The current in LED can be calculated by the

equation:

BP2831A_EN _DS_Rev.1.0

www.bpsemi.com

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