Patent ID: 7236118

Claim:
A multiple input AD conversion apparatus which converts a first analog input signal and a second analog input signal to a first digital output signal and a second digital output signal respectively, the multiple input AD conversion apparatus comprises: a first sample-and-hold circuit to sample and hold a first analog input signal; a second sample-and-hold circuit to sample and hold a second analog input signal; a first unit AD converter following the first sample-and-hold circuit and including a plurality of first conversion stages connected in cascade to convert the first analog input signal to the first digital output signal; a second unit AD converter following the second sample-and-hold circuit and including a plurality of second conversion stages connected in cascade to convert the second analog input signal to the second digital output signal; and a plurality of operational amplifiers each configured to be shared between a corresponding first conversion stage of the first conversion stages and a corresponding second conversion stage of the second conversion stages in a time sharing.