Phase-shift PWM simulation

Thread Starter

Alec_t

Joined Sep 17, 2013
14,405
Below is the simulation of PSPWM running Linear Technology's own test fixture of the LTC1922-1 (found in the LTspice Power Products folder).
I'm surprised at the messy state of the output voltage across the load. Is this the best the chip can do? I understood that PSPWM involved zero-voltage switching, supposedly to minimise switching noise.

1922-1_test.jpg
 

Ian0

Joined Aug 7, 2020
10,264
Looks like the error Amplifier is unstable. I would have expected another capacitor from comp to feedback.
 

ericgibbs

Joined Jan 29, 2010
19,084
hi eetech,
If you post your working asc file, I will try and see if that makes a difference.

Not sure what you mean, but...
I am pointing out that your sim shows a +5V out whereas mine shows around only ~+3 Vout

E
 

eetech00

Joined Jun 8, 2013
4,038
hi eetech,
If you post your working asc file, I will try and see if that makes a difference.
Done

Not sure what you mean, but...
I am pointing out that your sim shows a +5V out whereas mine shows around only ~+3 Vout

E
Sorry, that wasn't clear, I thought you were expecting the output to be 3v.

File is attached. The only thing I changed was the simulation time to match alex_t's.
 

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Thread Starter

Alec_t

Joined Sep 17, 2013
14,405
Thanks guys. I've also been using Trtol set to 7, 'cos that often seems to help convergence. I'll bear in mind how fiddling with it can make a big difference.
 
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