Tuesday, October 14, 2008

Analog to digital converter module

We have already seen about the need for analog to digital converters in my previous post. Now let us look into how the analog to digital converter module actually works. The below figure represents the analog to digital converter module.

You can see the input pins where the analog data comes from, which are connected to the inputs of an analog multiplexer. The function of the analog multiplexer is to connect the selected input channel to the holding capacitor. The holding capacitor is connected to the output of the analog multiplexer and when a conversion is initiated, the analog multiplexer disconnects all inputs from the holding capacitor, and the successive approximation converter performs the conversion on the voltage stored on the holding capacitor thus providing a digital value at the output.

1 comment:

Deepz said...

The Figure can be improved by adding another switch from the capacitor to the micro-logic block. Generally this is what we call a S-H circuit. Sample and Hold circuit. The micro generatlly doesnot ready the voltage when the cap is charging :-). Anyway nice read.