D/A conversion circuit, quantization circuit, and A/D conversion circuit
First Claim
1. A D/A conversion circuit having an output terminal connected to an input terminal of an operational amplifier that is connected to a quantization circuit, the D/A conversion circuit comprising:
- a DAC capacitor;
a selection switch that selectively switches among a reference potential, a first voltage higher than the reference potential, and a second voltage lower than the reference potential to apply to an input side of the DAC capacitor as an analog potential;
a ground switch that connects an output side of the DAC capacitor to an analog ground potential; and
an output switch that connects the output side of the DAC capacitor to the output terminal, wherein;
in a first period, the selection switch selects one of the reference potential, the first voltage and the second voltage according to one of four levels output from the quantization circuit as a quantization result value, and connects the one of the reference potential, the first voltage and the second voltage to the input side of the DAC capacitor, and the ground switch turns on to charge the DAC capacitor; and
in a second period subsequent to the first period, the selection switch selects one of the first voltage and the second voltage according to the one of four levels, and connects the one of the first voltage and the second voltage to the input side of the DAC capacitor, and the output switch turns on to output the analog potential having one of four levels to the output terminal from the DAC capacitor.
1 Assignment
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Accused Products
Abstract
A D/A conversion circuit includes: an output terminal connected to an operational amplifier connected to a quantization circuit; a DAC capacitor; a selection switch switching among reference, first and second voltages to apply to the DAC capacitor as an analog potential; a ground switch connecting the DAC capacitor to a ground; and an output switch connecting the DAC capacitor to the output terminal. In a first period, the selection switch selects one of the reference, first and second voltages according to a quantization result value from the quantization circuit, and connects the one to the DAC capacitor, and the ground switch turns on to charge the DAC capacitor. In a second period, the selection switch selects another one of the first and second voltages, and connects the another one to the DAC capacitor, and the output switch turns on to output the analog potential to the output terminal.
12 Citations
11 Claims
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1. A D/A conversion circuit having an output terminal connected to an input terminal of an operational amplifier that is connected to a quantization circuit, the D/A conversion circuit comprising:
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a DAC capacitor; a selection switch that selectively switches among a reference potential, a first voltage higher than the reference potential, and a second voltage lower than the reference potential to apply to an input side of the DAC capacitor as an analog potential; a ground switch that connects an output side of the DAC capacitor to an analog ground potential; and an output switch that connects the output side of the DAC capacitor to the output terminal, wherein; in a first period, the selection switch selects one of the reference potential, the first voltage and the second voltage according to one of four levels output from the quantization circuit as a quantization result value, and connects the one of the reference potential, the first voltage and the second voltage to the input side of the DAC capacitor, and the ground switch turns on to charge the DAC capacitor; and in a second period subsequent to the first period, the selection switch selects one of the first voltage and the second voltage according to the one of four levels, and connects the one of the first voltage and the second voltage to the input side of the DAC capacitor, and the output switch turns on to output the analog potential having one of four levels to the output terminal from the DAC capacitor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification