ADC Voltage scaling

Thread Starter


Joined Mar 20, 2012

Planning on using a STM8 microcontroller as an ADC to measure battery voltage.
Battery voltage range 5.5v to 9v (5-10v is a safe range if it makes the calculation easier).
The STM8 will be running off a 1.8v LDO supply.

How do I use a op-amp to voltage scale and offset the battery input so that I have maximum dynamic range for the ADC.

Ron H

Joined Apr 14, 2005
Which STM8 are you using? Please attach the datasheet, or provide a link to it.

Ron H

Joined Apr 14, 2005
How accurate do you need the measurement to be?
This is going to require a resistive voltage divider. If you can tolerate a small resistive load on the battery, you can avoid the use of an op amp.
Do you have a good digital multimeter that you could use to do a software calibration on the ADC output, to compensate for resistor tolerances?