short circuit protectection from smps to a voltage regulator

Status
Not open for further replies.

varunme

Advanced Member level 3
Joined
Aug 10, 2011
Messages
741
Helped
17
Reputation
36
Reaction score
17
Trophy points
1,318
Activity points
5,764
I want to build a variable voltage supply with LM317, which takes power from a PC smps,
I want to utilize the short circuit protection in smps, but after regulation with LM317, the protection is not working,
how can we implement that , after the regulation?
 

before LM317 put a series pass transistor to the emitter connect a resistor for your required current so that the dtop accross becomes .7V at max current and connect base and LM317 after the resistor connect collecter to unreg+
 

how can i implement that for a maximum of 10A load ?
 

For 10A load it is not advisable to use a series pass transistor because the heat from the transistor will be too much.
The maximum rating of lm317 is only 1.5 A , For a system of 1.5A the above system can be used with proper heatsink
 

10A load can be implemented by parallel power transistors
i am a bit lost with the implementation of the circuit breaker, if i can manually set the value of the current at which the circuit is breaked , then it will be more useful
 

it is possible pass the load current through a load resistor .1R amplify the voltage accross it using a opamp compare it with a ref voltage and trip the circuit .You can find all these features in IC LM723
 
Reactions: varunme

    varunme

    Points: 2
    Helpful Answer Positive Rating
Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…