stupid question , please help
kimo3010, Thu May 19 2016, 02:41PM
i am trying to duplicate loneoceans sstc then i am going to moified to drsstc then my own bigger drsstc
so now i am following this :
same interrupter used 555 timer to replicate feedback about 80kHZ .
but the when i scope the driver output
scope 1 pin7 -ground
scope 2 pin5 - ground
the both signals are non-inverted . so i suspected the INA , INB are different . scoped both , both signals are the same . but the output form the driver supposed to be non-inverted and inverted . what am i doing wrong here ?
Re: stupid question , please help
Blackcurrant, Thu May 19 2016, 07:36PM
Pin 1 high? If not why?
I hope you are not using the mains while testing this!
Use a small battery for the power and stay safe until you know what you are doing.
Re: stupid question , please help
Sulaiman, Fri May 20 2016, 06:45AM
first I would check that the IC is marked 27425, sometimes suppliers mess-up.
disconnect the primary & 1 uF load on the outputs and check operation,
if still in-phase then the 27425 is faulty.
I saw the note on the circuit diagram indicating 5 V output required from the interrupter
for testing disconnect the diode to the uvlo circuit as it may be confusing things.
Re: stupid question , please help
kimo3010, Fri May 20 2016, 08:46AM
i didn't connect the primary nor the 1 uf cap , i just scoped the outputs directly. is that wrong and if yes can you tell me why ! ?
Re: stupid question , please help
Sulaiman, Fri May 20 2016, 11:11AM
Provided that the low voltage section is isolated from the mains, live, neutral and earth, or 0 Vdc is mains earth, then no problem.