current sensing for hard disk

[SonOfZeus]

i am a newbie, working on a project, hoping someone can enlighten me on this:
- this project is to build a circuit to sense the current consumed by a hard disk and then pass on the measured current information to an adc and to a microcontroller for calculation
- components involved are op-amp, adc and microcontroller
- current measurement range is 10mA to 20A
- i have already decided on which adc and microcontroller to use
- i need advices on which op-amp to chose from, hopefully someone can teach me what to do or maybe someone can provide a full schematic diagram with all components' values
- thanks a million

 

[meysam_abbasinia]

hi , that is very simple, you shod sens current with very tiny resistor and convert to voltage. then with an opamp amplify your voltage in suitable range for your adc. and convert to digital.

that is not hard.

good luck.

 

[kender]

look at this app note: **broken link removed**
broader app note on current sensing. It covers both resistive and hall-effect sensors: **broken link removed**