DC DC converter problem with cct and shootky diode

[danesh]

dc dc converter

recently i built a dc dc converter which will regulate the output to 13.8V. i found that my pnp transistor had open cct and my shootky diode is shorted, after vithe cct went through vibration. Do any one have any solution y these failures occurs

 

[Btrend]

Re: dc dc converter

hi, ur description is too rough to help.
what is ur Vin ? step-down or step up? what topology u used?

 

[danesh]

Re: dc dc converter

i have used buck config.... vin is 13.8. i would like to knw how often a transistor gets fail in dc dc converter and what might contribute to it

 

[Ante]

Re: dc dc converter

Hi danesh,

Can you post the circuit and some output/input data, it might be easier to find the problem for you?

The problem can be self oscillation.

Ante

 

[Btrend]

Re: dc dc converter

recently i built a dc dc converter which will regulate the output to 13.8V. i found that my pnp transistor had open cct and my shootky diode is shorted, after vithe cct went through vibration. Do any one have any solution y these failures occurs

i have used buck config.... vin is 13.8. i would like to knw how often a transistor gets fail in dc dc converter and what might contribute to it

in buck, Vout=D*Vin, so Vout < Vin,
but ur spec is Vin=13.8 =Vout, so ur D=100%.... , don't u feel strange ?
it's not a SMPS, it's direct short of Vin and Vout ??? [/quote]

 

[rhesusmonkeyboy]

Re: dc dc converter

As folks mentioned some more info would help, so that we have all of the following

Vin
Vout
Filter Inductor?
Filter Cap?
Load?

Off the top of my head, do you have a resistor in series with the base? ( Assuming you're using a bipolar )

Is the device rated for the currents and voltages you expect ( peaks, rms )? How much current and voltage can it handle?

Is it possible the required load current is destroying your devices?

Actually, I guess I asked the same question in 3 different ways, but you get my idea I hope!

^-^

We look forward to more info, so we can help!