Analog to digital converter with inverter based amplifier
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorMartin Kinyua
Life of this patent
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Abstract
An analog-to-digital converter (“ADC”) includes an input terminal configured to receive an analog input voltage signal. A first ADC stage is coupled to the input terminal and is configured to output a first digital value corresponding to the analog input voltage signal and a first analog residue signal corresponding to a difference between the first digital value and the analog input signal. An inverter based residue amplifier is configured to receive the first analog residue signal, amplify the first analog residue signal, and output an amplified residue signal. The amplified residue signal is converted to a second digital value, and the first and second digital values are combined to create a digital output signal corresponding to the analog input voltage signal.
Claims20
An analog-to-digital converter (“ADC”), comprising:
- first and second input terminals configured to receive an analog input voltage signal;
- a first ADC stage coupled to the input terminal and including:
- a sample and hold circuit comprising an array of binary weighted capacitors configured to sample the analog input voltage signal;
- a successive approximation register (SAR) ADC configured to convert the analog input voltage signal to a first digital value;
- a digital-to-analog converter (DAC) configured to receive the analog input voltage signal and the first digital value, and output a first analog residue signal;
- a first amplifier stage configured to receive the first analog residue signal;
- a second amplifier stage configured to receive an output of the first amplifier stage;
- a third amplifier stage configured to receive an output of the second amplifier stage and output a first amplified residue signal;
- a second ADC stage configured to receive the first amplified residue signal and output a second digital value corresponding to the first amplified analog residue signal;
- and
- a controller configured to combine the first and second digital values into a digital output signal representing the analog input voltage signal.
An analog-to-digital converter (“ADC”), comprising:
- an input terminal configured to receive an analog input voltage signal;
- a first ADC stage coupled to the input terminal and configured to output a first digital value corresponding to the analog input voltage signal and a first analog residue signal corresponding to a difference between the first digital value and the analog input signal at a residue output terminal;
- a first amplifier stage having an input inverter coupled between first and second voltage terminals and connected to the residue output terminal;
- a second amplifier stage having first and second inverters coupled between the first and second voltage terminals and connected to an output terminal of the first amplifier stage, the second amplifier stage having first and second control transistors configured to respectively control current flow through the first and second inverters in response to respective control signals;
- and
- a third amplifier stage including an output inverter coupled between the first and second voltage terminals and connected to an output terminal of the second amplifier stage.
A method, comprising:
- receiving an analog input voltage signal;
- determining a first digital value corresponding to the analog input voltage signal;
- determining a first analog residue signal corresponding to a difference between the first digital value and the analog input;
- receiving the first analog residue signal by an input inverter of a first amplifier stage, wherein the input inverter is coupled between first and second voltage terminals;
- receiving an output of the first amplifier stage by first and second inverters of a second amplifier stage, wherein the first and second inverters of the second amplifier stage are coupled between the first and second voltage terminals;
- applying respective control signals to gate terminals of first and second control transistors to control current flow through the first and second inverters of the second amplifier stage;
- receiving an output of the second amplifier stage by an output inverter of a third amplifier stage, wherein the output inverter is coupled between the first and second voltage terminals;
- and
- outputting an amplified analog residue signal by the third amplifier stage.
Dependencies are inferred from the claim text.