US 8,477,058 B2 · Successive approximation analog to digital converter with a direct switching technique for capacitor array through comparator output and method thereof

Abstract

A method for a successive approximation register ADC which includes at least one capacitor array and a plurality of switches is provided, in which the capacitors of the capacitor array are one-to-one corresponding to the switches. The method includes the following steps: firstly, at least one multiplexer is configured. Then, a first comparison voltage is outputted based on the terminal voltages on the terminals of the capacitor array, and a comparison result is outputted according to the first comparison voltage and a second comparison voltage. Afterwards, a sequence of comparisons is controlled based on the comparison result to enter into a sequence of comparison phases. Finally, the switches are orderly selected, by the multiplexer based on the comparison phases, to switch directly according to the comparison result.

Claims14

Dependent claims

A successive approximation ADC (SAR ADC), comprising:

a first digital to analog converter (DAC) comprising a first capacitor array and a plurality of first switches, wherein the capacitors of the first capacitor array are one-to-one corresponding to the first switches;
SAR control logic configured to control to enter into a sequence of comparison phases sequentially;
a comparator, coupled to the first DAC, configured to output a first comparison result based on a first comparison voltage of the first DAC and a second comparison voltage;
and
a first multiplexer, coupled between the comparator and the SAR control logic, configured to select one of the first switches, based on the currently comparison phase entered by the SAR control logic, to be switched directly according to the first comparison result;
wherein the first multiplexer comprises a plurality of latch circuits which are one-to-one corresponding to the first switches.

3 more elements

A method for a successive approximation ADC (SAR ADC) which comprises at least one capacitor array and a plurality of switches, wherein the capacitors of the capacitor array are one-to-one corresponding to the switches, and the method. comprising:

configuring at least one multiplexer;
outputting a first comparison voltage based on the terminal voltages on the terminals of the capacitor array;
outputting a comparison result based on the first comparison voltage and a second comparison voltage;
controlling a sequence of comparisons based on the comparison result to enter into a sequence of comparison phases;
and
selecting the switches in order, by the multiplexer based on the comparison phases, to be switched directly according to the comparison result;
wherein the multiplexer comprises a plurality of latch circuits which are one-to-one corresponding to the switches, and the multiplexer turns on the latch circuits sequentially based on the sequence of comparison phases, so as to sequentially output the comparison results, generated in the sequence of comparison phases, to switch the corresponding switches.

4 more elements

Dependencies are inferred from the claim text.

Successive approximation analog to digital converter with a direct switching technique for capacitor array through comparator output and method thereof

Life of this patent

Successive approximation analog to digital converter with a direct switching technique for capacitor array through comparator output and method thereof

Life of this patent

Abstract

Claims14