OVP circuit

120

03:02:44

Over Voltage Protection 
Discrete 회로 구성
(zener 응답속도가 빠르지 않으면 slewrate가 큰 전압에 대해서는 보호가 어려울 수 있음)


동작
1.  Vz(zener break Voltage)보다 작은 전압이 걸리면 
mos1(왼쪽)이 off
mos2(오른쪽)이 on됨 
-> Load로 전류 흐름 (로드에 걸리는 전압은 맨 오른쪽 저항값 만큼)

2. Vz보다 큰 전압이 걸리면
mos1 : ON
mos2 : OFF
-> mos1이 On되므로 mo1의 Drain쪽이 Source 전압과 비슷해짐 -> mos는 거의 off됨(mos2의 Vgs=0) 
-> Load 로 전류 흐르지 않음 (전압 거의 안걸림)

published 7 years ago

PrathikP

7 years ago

Using a bjt in place of the pull up MOSFET would be a better option

PrathikP

7 years ago

Or you could use a logic level MOSFET

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