Analog-to-digital converter for a multi-channel signal acquisition system

A signal acquisition system comprising:

• a plurality of input channels;
• an analog-to-digital converter (ADC) comprising:
• a sample-and-hold (S/H) circuit for each input channel, and operable to receive a respective analog input signal for each input channel;
• a digital-to-analog converter (DAC) common to all input channels;
• a comparator for each input channel, said comparator configured to receive an output signal from the S/H circuit of the respective input channel as a first input signal, and an output signal from the DAC as a second input signal, for generating a comparison result at each conversion cycle of the comparator;
• and
• a successive approximation register (SAR) common to all input channels and configured to generate a digital output signal;
• and
• a digital multiplexer (MUX) configured to receive the comparison results from the respective comparators as inputs and multiplex said comparison results prior to inputting to the SAR for generating the digital output signal.

A method of generating a digital output code from an analog input signal received at an input channel of a plurality of input channels, the method comprising the steps of:

• receiving said analog input signal at a sample-and-hold (S/H) circuit and a comparator for said input channel;
• providing a digital-to-analog converter (DAC);
• comparing, at the comparator, a first input signal received from the S/H circuit of said input channel with a second input signal received from the DAC for generating a comparison result at each conversion cycle of the comparator;
• and
• generating, at the a successive approximation register (SAR) common to all input channels, the digital output code based on the comparison results received from the comparator for said input channel.

A method of converting a plurality of analog input signals to a digital output signal, the method comprising the step of:

• providing a plurality of input channels;
• receiving the respective analog input signal at a sample-and-hold (S/H) circuit and a comparator for each input channel;
• providing a digital-to-analog converter (DAC);
• comparing, at the comparator, a first input signal received from the S/H circuit of the respective input channel with a second input signal received from the DAC for generating a comparison result at each conversion cycle of the comparator;
• multiplexing, using a digital multiplexer (MUX), the comparison results received from the respective comparators;
• and
• generating, at a successive approximation register (SAR) common to all input channels, a digital output signal based on the multiplexed signal.