Analog-to-digital converter for programmable logic
AssigneeAltera Corporation
InventorsTony San, Jinyan Zhang
Life of this patent
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Abstract
Digital-to-analog and analog-to-digital conversion are implemented in or using programmable logic. The DAC and ADC circuits may be hardwired in a programmable logic integrated circuit or may be implemented using an intellectual property (IP) core. The IP core would be a series of bits to configure the logic cells and other programmable logic of an integrated circuit to include one or more DACs or ADC, or both on the same integrated circuit. The DAC may be a sigma-delta-modulator-based implementation or a resistor-ladder-based implementation.
Claims21
An integrated circuit comprising:
- an analog-to-digital converter comprising:
- a digital-to-analog converter;
- a comparator having a first input coupled to an output of the digital-to-analog converter and a second input coupled to receive an analog input voltage;
- a successive approximation register having an input coupled to an output of the comparator;
- and
- a memory having an input coupled to an output of the successive approximation register and an output coupled to an input of the digital-to-analog converter, wherein the output of the digital-to-analog converter is coupled to the first input of the comparator.
A method of converting analog signals to digital signals comprising:
- performing a calibration by:
- converting a first digital signal to a first analog signal;
- converting a second digital signal to a second analog signal;
- comparing the first analog signal to the second analog signal;
- and
- storing a digital entry, the digital entry based on the comparing the first analog signal to the second analog signal;
- then
- converting a third analog signal to a third digital signal by:
- using the digital entry to generate a fourth digital signal;
- converting the fourth digital signal to a fourth analog signal;
- comparing the fourth analog signal to the third analog signal;
- and
- producing the third digital signal based on the comparison of the fourth analog signal to the third analog signal.
An integrated circuit comprising:
- an analog-to-digital converter comprising:
- a memory;
- a first digital-to-analog converter having an input coupled to the memory;
- a first comparator having a first input coupled to an output of the first digital-to-analog converter and a second input coupled to receive an analog input voltage;
- and
- a successive approximation register having an input coupled to an output of the first comparator and an output coupled to an input of the memory;
- and
- a calibration loop comprising:
- a second digital-to-analog converter;
- a second comparator having a first input coupled to an output of the second digital-to-analog converter and a second input coupled to the output of the first digital-to-analog converter;
- and
- a calibration logic circuit having an input coupled to an output of the second comparator and coupled to write data to the memory.
Dependencies are inferred from the claim text.