Hi Guys
Customer asked:
I have a circuit design (see below) where I am injecting a PWM signal (from a microcontroller) into a Opamp to produce a 0-10V dc output (effectively a simplified DAC).
The circuit works fine (changing the PWM mark to space ration provides a good controllable linear 0 to 10V signal.
I was wondering if you had any ideas on either a different opamp or some additional circuitry to protect the amplifiers potential high output from someone shorting it to ground ?
At the moment I have put two 1k ohm resistors in parallel (for heat distribution) so that the opamps output current is not exceeded if a direct short is place on the unit.
This kind of works but I am concerned that the output will always need to drive into a very high impedance input to avoid any voltage drops (i.e. potential divider made from the 500R output impedance and the load input)
I think some amplifiers are available with internal current limiting protection, or is there anything else that you may suggest?
Thanks
Rodney