Patent ID: 7397287

Claim:
A sample hold circuit for sampling and holding an input voltage, the sample hold circuit comprising: an operational amplifier that converts the held voltage to a differential output voltage, the operational amplifier having inverting and non-inverting input terminals and inverting and non-inverting output terminals; a first plurality of first capacitors each of which is connected to the inverting input terminal; a second plurality of second capacitors each of which is connected to the non-inverting input terminal, the second capacitors being paired with the first capacitors to provide a plurality of capacitor pairs in each of which the first and second capacitors have a same capacitance; and a control circuit that applies the input voltage to at least one of the first and second capacitors and a predetermined voltage to others of the first and second capacitors in a sampling phase and that connects at least one of the capacitor pairs to the inverting and non-inverting output terminals such that the first and second capacitors of the at least one of the capacitor pairs are connected to the non-inverting and inverting output terminals, respectively, and applies the input voltage to at least one of the first and second capacitors of others of the capacitor pairs in a holding phase, wherein a total capacitance of the first and second capacitors to which the input voltage is applied in the sampling phase is equal to a total capacitance of the first and second capacitors to which the input voltage is applied in the holding phase, a total capacitance of the first capacitors to which the input voltage is applied in the holding phase is equal to a total capacitance of the second capacitors to which the input voltage is applied in the holding phase, and a total capacitance of the first capacitors to which the input voltage is applied in the sampling phase is different from a total capacitance of the second capacitors to which the input voltage is applied in the sampling phase.