US Patent 7952509 Successive approximation A/D converter

A successive approximation A/D conversion circuit for simultaneously sampling N channels of analog signals and for A/D converting the sampled analog signals, includes: N capacitive main DACs; a resistive sub DAC; N comparators; and a successive approximation control circuit, wherein the successive approximation control circuit determines high-order bit values of A/D conversion results of the N channels of analog signals by controlling the N capacitive main DACs and the N comparators, and determines low-order bit values of the A/D conversion results of the N channels of analog signals by controlling the resistive sub DAC and the N comparators.