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 : Link2
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
kimo3010, Fri May 20 2016, 05:11AM

using 12v power supply

pin1 is getting the output form the interrupter both pin 1 and 8 are high and low at the same time . same with pin 4&2 getting the output of the 555 timer aprrox 82khz .

according to the datasheet : https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwjk9IKn8efMAhVLJpQKHYT1DCkQFgg0MAE&url=http%3A%2F%2Fwww.ti.com%2Flit%2Fgpn%2Fucc27424&usg=AFQjCNHDYUOSNXOvRRM1WhKuds4g0z_muw&sig2=7e5aroa42r03zJwztE8smg&bvm=bv.122448493,d.dGo
setup i should get pin 7 non-inverted pin 5 inverted
but when i scope both output i get same wave form non-inverted
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.
Re: stupid question , please help
kimo3010, Fri May 20 2016, 05:46PM

ohhh because my power supply is something like this http://n3.sdlcdn.com/imgs/a/m/1/Varsa-Power-Adapter-12v-2a-SDL314253267-1-84928.jpg
is that the reason why i am getting both same non-inverted signal ?


note : i am using a 0.5A FAST ACTING fuse to protect my circuit if i miss up .