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US 6,188,343 B1Granted
Method and structure for providing a digitally controlled voltage gain amplifier with non-linear gain adjustments
AssigneeNational Semiconductor Corporation
InventorSteven O. Smith
Life of this patent
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Abstract
A non-linear function of an input voltage is provided by cascading multiplying digital-to-analog converters (mDACs) to provide a polynomial power series to approximate the non-linear function. Weighting functions are provided by fixed gain amplifiers.
Claims13
A digitally-controlled voltage gain amplifier circuit capable of non-linear voltage adjustments, comprising:
- a fine gain amplifier receiving an analog input signal and an analog gain adjustment signal to provide an output analog signal having a value that is a function of said analog input signal and said analog gain adjustment signal;
- and
- a gain control circuit receiving a digital value and providing said analog gain adjustment signal, said gain control circuit comprising:
- a first multiplying digital-to-analog converter receiving a reference voltage and said digital value to provide a first output voltage proportional to said reference voltage and said digital value;
- a second multiplying digital-to-analog converter receiving said first output voltage and said digital value to provide a second output voltage proportional to said reference voltage and a square of said digital value;
- and
- a summing circuit receiving said first and second output voltages and said reference voltage to provide a sum thereof as said analog gain adjustment signal.
4 more elements
A method for providing a digitally-controlled voltage gain amplifier circuit capable of non-linear voltage adjustments, comprising:
- (i) receiving an analog input signal;
- (ii) receiving an input a digital value representative of a parameter one of said non-linear voltage adjustments;
- (iii) generating from said digital value an analog gain adjustment, said generating comprises:
- (a) providing a first multiplying digital-to-analog converter receiving a reference voltage and said digital value to provide a first output voltage proportional to said reference voltage and said digital value;
- (b) providing a second multiplying digital-to-analog converter receiving said first output voltage and said digital value to provide a second output voltage proportional to said reference voltage and a square of said digital value;
- and
- (c) summing said first and second output voltages and said reference voltage to provide said analog gain adjustment signal;
- and
- (iv) amplifying said analog input signal according to said analog gain adjustment signal to provide an analog output signal.
6 more elements
Dependencies are inferred from the claim text.