AP3785T

Document number: DS37552 Rev. 4 - 2

3 of 18

www.diodes.com

September 2015

© Diodes Incorporated

AP3785T

T1

CY1

+

C5

+

C6

IC2

APR34XX

R11

VCC

AREF

DRAIN

DRAIN

GND

GND

VDET

DRISR

R13

C9

R14

C8

C7

R12

+

C1

FR1

+

C2

L1

FB

R5

OUT

VCC

OTP

IC1

CBC

GND

R1

R 2

R7

Q1

D1,D2,

D3,D4

L2

R9

C4

D7

R4

D6

C3

EM

CS

R10

R6

D5

R 8

AP3785T

R3

NTC1

Note 4: If the OTP pin is not connected to the NTC resistor, the external OTP function will not work and the IC can still work normally with internal OTP.

Pin Descriptions

Pin Number

Pin Name

Function

1

CS

Sense primary side current for turning off the external power MOSFET and deliver a voltage

proportional to the line voltage for compensation from FB pin

2

EM

Connected to the source of external power MOSFET

3

VCC

The power supply for the IC. In order to get the correct operation of the IC, a capacitor with low

ESR should be placed as close as possible to the VCC pin

4

OUT

Turn on and turn off the external power MOSFET

5

GND

The ground of the IC

6

OTP

The external over temperature protection

7

CBC

This pin connects a resistor to GND for output cable voltage drop compensation

8

FB

Voltage feedback. The CV and CC regulation are realized based on the voltage sampling of this

pin