Re: programmable circuit breaker

On 06-03-2025 00:55, john larkin wrote:

On Wed, 5 Mar 2025 15:36:22 -0800, Buzz McCool <buzz_mccool@yahoo.com>
wrote:
 

On 3/4/2025 9:06 PM, john larkin wrote:
...

>
So how might a user program a circuit breaker? Just RMS current with
some time constant? Allow fast and slow trips?

>
I've designed an electronic circuit breaker using Linear Technology
(now Analog Devices) hot swap controllers. It looks like they offer
some products with a programmable current limit.
>
I'm not sure if you can change the circuit breaker time delay though.
>

 I used a TI e-fuse chip in one product. TPS26600. It liked to blow up.
Being a nasty power-pad chip, it was very hard to replace.
 AP22652 is cool. We use it to current limit the power into pulse
generator output drivers.
 On our relay board, we'll have a Hall effect current sensor driving a
fast ADC, and the shutdown will be FPGA code, so we can do most
anything.
  

I am working on a solid state circuit breaker. So instead of your relay, I have two IGBTs back to back for ac operation.
You can do more than just measure the current. I have added an inductor on the output, so in case of a short and umlimited power on the primary side, the current rises defined before saturation.
You can detect the voltage over the switch/inductor, if too high you have a short. That will probably be much faster than the hall sensor
The inductor will limited the dI/dt, so the IGBTs are turned off before SOA is reached. Kick back pulse must be diverted off course, when/if the load decides not to be a short any more at the peak of the current ramp.