LD9162K

03/10/2021

14

Leadtrend Technology Corporation

www.leadtrend.com.tw

LD9162K-DS-00 March 2021

Where

VDC_BNI is predicted BNI DC value of input voltage.

VDC_BNO is predicted BNO DC value of input voltage.

VDC_BULK_OVP is predicted BULK_OVP DC value of input

voltage.

IBNI is BNI trip current, IBNO is BNO trip current.

IBULK_OVP is BULK OVP trip current.

Np is turns ration of primary-side winding.

Na is turns ration of auxiliary winding.

Fig. 20

Over Voltage Protection on FB Pin (FB OVP)

– Auto Recovery

An output overvoltage protection is implemented in the

LD9162K. The auxiliary winding voltage can be reflected

from secondary winding, in which the FB pin voltage is

proportional to output voltage during the gate off time.

OVP is worked by sensing the auxiliary voltage via the

divided resistors Rb, refereeing to Fig. 22. If VFB overs the

FB OVP trip level, the internal counter starts counting 6

cycles,

and

then

LD9162K

goes

to

auto-recovery

protection mode till the FB OVP status is defused.

Fig. 21

Fig. 22

95µA

t

Vcc

t

Drain

Switching

Non-Switching

t

IFB

t

Line Voltage

85µA

Non-

Switching

Normal Range

UVLO(on)

UVLO(off)

LD9162K

Ra

Rb

VCC

FB

GND

VFB

380µA

t

De-Bounce Time

t

OUT

Switching

t

IFB

t

Line Voltage

Non-Switching

Switching

450ms