I don't think any MCU has current sense on its own. What can be easily
implemented is a current sense circuit connected to an A/D input.
In its simplest form it is just a sense resistor and a few protection
parts (more resistors, Zener diode, capacitor). Some more sophisticated
forms may include operational amplifiers or a current sense IC.

Cheers,
Isaac


Em 10/02/2017 20:06, Jim Ruxton escreveu:
>
> On 2017-02-10 04:42 AM, alan.b.pearce@stfc.ac.uk wrote:
>>>> This is why I suggested using a high side current sense chip like the =
Linear
>>>> Technology LTC6101, LTC6102, LT6106 or Microchip PAC1921.
>>>> These would work with a PCB trace at about that resistance and feeding
>>>> that into an ADC would allow configurable current monitoring.
>>> This sounds like a good idea.  Some nice chips here.. Just wondering if=
 I put
>>> the voltage out of these chips  into an ADC on my PIC if that would be =
fast
>>> enough to catch a short before my FET fries. I'll have to take a closer=
 look at
>>> the time it would take to read the ADC and take action. Because I am us=
ing
>>> PWM ( around 15 KHz ) I guess I would need to
>>> synchronize my ADC reading with the on state.   I have read that FETs
>>> can burn out fairly quickly ie. 10 uSec so the conversion and taking ac=
tion to
>>> turn off the FET would have to occur fast.
>>> Jim
>> I assumed that as you mentioned PWM control of the FETs that there would=
 be a micro involved to drive the PWM, and that the current sense chip woul=
d feed the micro. The micro would then handle a serial comms link to a PC f=
or a source of commands re LED brightness etc., and to supply the PC with e=
rror/diagnostic information.
>>
>> There are PIC chips designed for motor control that have a current sense=
 feedback input to allow the drive to the motor to be turned off but I don'=
t think these would act correctly for driving LEDs.
> In this case there are no computers involved. The board will have an LCD=
=20
> display for feedback. And yes there is a PIC controlling the PWM, LCD=20
> display etc. I didn't realize there were PICs with current sense. I will=
=20
> look in those.
> Thanks for the help.
> Jim


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