Analog computation circuits using synchronous demodulation and power meters and energy meters using the same
AssigneeLinear Technology Corporation
InventorJoseph G. Petrofsky
Life of this patent
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Abstract
The present invention relates to analog computation circuits that use a synchronous demodulator topology which can be configured to perform arithmetic computation, power measurements, and/or energy measurement of various analog signals. The computation circuits have circuitry that generates an output signal based on the values of a first input signal, a second input signal, and a reference signal. This invention provides accurate computation of two signals by using modulation circuitry (e.g., Δ-Σ modulation circuitry), demodulation circuitry (e.g., multiplying digital-to-analog converters), delay circuitry, and output circuitry.
Claims41
Analog computation circuitry that generates an output signal at an output node proportional to a first input signal at a first input node, a second input signal at a second input node, and inversely proportional to a reference signal at a reference node, said circuit comprising:
- modulation circuitry that samples said first input signal and said reference signal based on a clock signal, said modulation circuitry generating at least one digital output signal;
- delay circuitry that delays said second input signal by generating at least one delayed second signal;
- demodulation circuitry that receives said at least one delayed second input signal and said at least one digital signal, said demodulation circuitry generating a product signal based on said at least one digital output signal and said delayed second signal;
- and
- output circuitry that receives said product signal, said output circuitry generates said output signal.
An analog computation circuit having a first and second input signal, a reference signal, a clock signal, and an output signal, said circuit comprising:
- a modulator, coupled to receive said first input signal and said reference signal, that generates at least one digital output signal based on said first input signal and said reference signal;
- a delay stage, coupled to receive said second input signal, which generates at least one delayed signal, that compensates for delay caused by said generation of said at least one digital output signal;
- a demodulator, coupled to receive said at least one said delayed signal and said at least one digital output signal, said demodulator generates a product signal based on said delayed signal and said digital output signal;
- and
- an output circuit, coupled to receive said product signal to produce said output signal.
A method for generating an output signal based on first and second input signals and a reference signal, said method comprising:
- modulating said first input signal with respect to said reference signal to generate at least one digital output signal;
- delaying said second input signal to generate at least one delayed second input signal to compensate for delay caused by said generation of said at least one digital output signal;
- demodulating said at least one digital output signal and said at least one delayed second input signal to produce a product signal;
- and
- processing said product signal to generate said output signal.
Dependencies are inferred from the claim text.