［AP2152］

MS1348-E-00

12

2012/05

Internal Nch FET on PGOOD pin operation

●Turn off during normal operation

●Turn on when abnormal operation

Timer latch off (Over current, CH short, Thermal protection), all CH are open or short, UVLO

●Turn on when in standby state while supply voltage (VIN) is applied. Turn off when VIN is less than 2V

●Turn on without delay by timer circuit when OVP pin short is detected.

Figure6.

PGOOD pin operation

Figure7.

Cut off VIN-LED anode path by using an external FET (example)

VPWM

VIN

VIN

PWM

Initial determination

1/10 *ILED

ILED

LED setting current

30ms typ

1ms

LED Current

Soft Start

PGOOD

PGOOD

PGOOD

PGOOD

ON

OFF

OFF

ON

About 2V

OFF

About2V

0.3ms typ

VIN

8

LX

15

PGOOD

L

D

VIN

1

LED Anode

3. 3V