| 摘要 |
An A/D converter includes a delta-sigma processing circuit for A/D conversion by delta-sigma modulation, and a cyclic processing circuit for A/D conversion by cyclic processing of amplification of a residue generated in the A/D conversion. The A/D converter further includes a quantization part for outputting a quantized value of quantized output of the delta-sigma processing circuit and a quantized output of the cyclic processing circuit, and a control circuit for generating an A/D conversion result and switching over a reference voltage based on the quantized value. The delta-sigma processing circuit and the cyclic processing circuit include a sampling capacitor, an integration capacitor and a capacitive D/A converter, which includes a DAC capacitor and add and subtract a charge corresponding to a reference voltage to and from a residue of quantization. The sampling capacitor, the DAC capacitor and the integration capacitor are provided as electrically separate capacitors. |
| 主权项 |
1. An A/D converter comprising:
a delta-sigma processing circuit for receiving an analog input signal for A/D conversion of the analog input signal by delta-sigma processing of delta-sigma modulation; a cyclic processing circuit for A/D converting, by cyclic processing, a difference between an amplified residue of quantization generated in the A/D conversion and a reference voltage; a quantization circuit for outputting a quantized value of a quantized output of the delta-sigma circuit and a quantized output of the cyclic processing circuit; and a control circuit for generating an A/D conversion result of the analog input signal based on the quantized value and outputting a control signal for switching over the reference voltage, wherein the delta-sigma processing circuit and the cyclic processing circuit include an operational amplifier forming an operation circuit, sampling capacitors, a capacitive D/A converter having a DAC capacitor for adding and subtracting the residue of quantization based on the reference voltage corresponding to the control signal, the delta-sigma processing circuit includes an integration capacitor used for the delta-sigma processing and the cyclic processing, and the sampling capacitors, the DAC capacitor and the integration capacitor are provided to be electrically separated. |
