EV4088-S-00A – HIGH LINE VOLTAGE, 5.5W LOW COST DIMMABLE LED DRIVER

EV4088-S-00A Rev.1.0

www.MonolithicPower.com

4

12/2/2015

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CIRCUIT DESCRIPTION

The EV4088-S-00A is configured in a single-

stage Buck-boost topology and gets a cost

effective BOM. It also achieves high power factor

and excellent TRIAC dimming performance.

R1, R2, and BD1 compose the input stage. The

resistors R1, R2 are used as a passive damper

of dimming. The diode rectifier BD1 rectifies the

input line voltage.

L1, L2, R3, R4, C1 and C2 form a π EMI filter.

R5, C3, and D2 form a RCD snubber to obtain

good surge test performance, the surge spike

energy will be absorbed by the electrolytic cap

C3.

R7, C4 are used as a bleeder which keeping the

TRIAC current above the minimum holding

current after leading edge dimmer turns on. The

D3, R6 are used to reduce the big capacitance

influence after trailing edge dimmer turns off and

improve the trailing edge dimming.

C5 is used to supply the power for MP4088. The

power is charged by the internal high voltage

regulator from HV pin.

R8 and R9 are used to monitor the output OVP

condition. The OVP voltage is set by the divider

ratio of R8 and R9.

R10, R12 are sensing resistors for LED current

control. The value of R10 and R12 set the output

LED current.

Diode D1 is the Buck-boost fly-wheel diode, the

inductor L3 and the capacitor C6 are the output

filter. The resistor R11 is placed as a dummy

load to consume the output power in open load

condition. The diode D4 is used to prevent the

output current flowing back to IC when input Sine

voltage drops lower than output voltage.