Dynamic compensation of analog-to-digital converter (ADC) offset errors using filtered PWM
First Claim
1. A system for providing dynamic compensation of analog-to-digital converter offset errors, comprising:
- an Analog-to-Digital Converter (ADC) having an analog input, a digital output, and at least one reference voltage input;
a waveform generator operative to produce at least one output signal having Pulse-Width Modulated (PWM) waveform characteristics, the output signal having at least one predetermined PWM waveform characteristic;
a low pass filter configured to receive the output signal having PWM waveform characteristics, to produce a corresponding DC output signal, and to provide the DC output signal to the reference voltage input of the ADC; and
a processor operative to detect a voltage offset at the ADC digital output, and to control the predetermined characteristic of the output signal based on the detected offset, thereby dynamically compensating for ADC offset errors.
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Abstract
A system and method of dynamic offset compensation that is particularly adaptable to analog-to-digital conversion performed in control applications employing highly integrated Digital Signal Processor (DSP) devices. The system providing dynamic compensation of Analog-to-Digital Converter (ADC) zero level offset errors includes an integrated DSP device with a multi-bit ADC and a PWM waveform generator for producing at least one PWM output, and an external low pass filter. The ADC receives an analog input signal and converts it into a corresponding digital output signal. The DSP device measures the zero level offset of the ADC output signal, and dynamically controls characteristics of the PWM output based on the measured offset. The low pass filter receives the PWM output and applies a corresponding controlled DC output voltage to the low reference voltage input of the ADC to dynamically compensate for the zero level offset error.
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Citations
20 Claims
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1. A system for providing dynamic compensation of analog-to-digital converter offset errors, comprising:
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an Analog-to-Digital Converter (ADC) having an analog input, a digital output, and at least one reference voltage input;
a waveform generator operative to produce at least one output signal having Pulse-Width Modulated (PWM) waveform characteristics, the output signal having at least one predetermined PWM waveform characteristic;
a low pass filter configured to receive the output signal having PWM waveform characteristics, to produce a corresponding DC output signal, and to provide the DC output signal to the reference voltage input of the ADC; and
a processor operative to detect a voltage offset at the ADC digital output, and to control the predetermined characteristic of the output signal based on the detected offset, thereby dynamically compensating for ADC offset errors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of providing dynamic compensation of analog-to-digital converter offset errors, comprising the steps of:
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providing an Analog-to-Digital Converter (ADC) having an analog input, a digital output, and at least one reference voltage input;
producing at least one output signal having Pulse-Width Modulated (PWM) waveform characteristics, the output signal having at least one predetermined PWM waveform characteristic;
filtering the output signal having PWM waveform characteristics by a low pass filter to produce a corresponding DC output signal;
providing the DC output signal to the reference voltage input of the ADC;
detecting a voltage offset at the ADC digital output by a processor; and
controlling the predetermined characteristic of the output signal based on the detected offset, thereby dynamically compensating for ADC offset errors. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification