AP3783R datasheet(13/17 Pages) DIODES

13 / 17 page

AP3783R

Document number: DS37448 Rev. 5 - 2

13 of 17

www.diodes.com

October 2015

AP3783R

Operation Principle Description (Cont.)

Figure 6 is the AP3783R normal start-up waveform that the voltage of FB pin is above VFB(SCP) during tSCP after VCC gets to the VTH_ST, which

doesn

’t enter the SCP mode. As shown in Figure 7, V

OUT is short and the voltage of FB pin is lower than V

FB(SCP) during tSCP, the AP3783R

triggers the SCP and enter the hiccup mode.

VTH_ST

VFB(SCP)

tSCP

VCC

VFB

VOUT

VOUT(SCP)

Figure 6. Normal Start-up

VTH_ST

VOPR(MIN)

VFB(SCP)

tSCP

VCC

VFB

VOUT

Figure 7. Short Circuit Protection (SCP) and Hiccup Mode

OVP

The AP3783R includes output over-voltage protection (OVP). If the voltage at FB pin exceeds VFB(OVP), the AP3783R immediately shuts down

and keeps the internal circuitry enabled to discharge the VCC capacitor to the UVLO turn-off threshold. After that, the device returns to the start

state and a start-up sequence ensues.

OTP

If the junction temperature reaches the threshold of +140

⁰C, AP3783R shuts down immediately. Before VCC voltage decreases to UVLO, if the

junction temperature decreases to +100

⁰C, AP3783R can recover to normal operation. If not, the power system enters restart Hiccup mode until

the junction temperature decreases below +100

⁰C.

AP3783R 데이터시트(PDF) 13 Page - Diodes Incorporated