It’s too difficult for beginners.

kzmugi

It’s too difficult for beginners. [Copy link]

 

Is this circuit not working? Experts, 18V is increased to 20V and then reduced to 9V, 12V, and 18V. When powered on, when the 18V output is on, the indicator light flashes, and the output of the boosted 20V becomes lower than 11V and jumps. When it is dialed to 9V, the output is normal, and then it is dialed back to 18V and the output is normal, without flashing. What is the problem?

maychang

One possibility is that U7U8 is under heavy load, and when powered on, U6 needs to charge the capacitors, resulting in a large current, causing U6 to be protected.

hungchou

時序，同時建立對U6而言瞬間電流過大

U7、U8的EN延遲即可

待U6輸出電壓建立完成穩定後，U7、U8再開始建立，U6的電流就不會過大

kzmugi

maychang posted on 2021-1-12 18:55 One possibility is that U7U8 is heavily loaded, and when powered on, U6 needs to charge the capacitors, the current is large, and U6 is protected.

Thank you for your answer. This should be the case. I enabled the delay of U7 and U8. It works normally for now. I will try a smaller capacitor later.

kzmugi

hungchou 发表于 2021-1-13 05:52 時序，同時建立對U6而言瞬間電流過大 U7、U8的EN延遲即可 待U6輸出電壓建立完成穩定後，U7、U8再開始 ...

Thank you, I tried to enable the delay and it works fine.

g6g6

God does exist