Wattmeter comprising a hall sensor and an A/D converter
First Claim
1. Wattmeter including a Hall sensor circuit and an A/D converter, said Hall sensor including a plurality of Hall elements for producing a plurality of sensor voltages, said A/D converter comprising an impulse-width delta modulator, an impulse shaper, first and second frequency dividers with division ratios N and M, respectively, said frequency dividers connected to said impulse shaper, a compensation circuit for generating a compensation voltage, an adding circuit which receives said plurality of sensor voltages, a reference voltage, and said compensation voltage, a source for producing said reference voltage, said adding circuit producing an output signal fed to the input of said modulator, and a clock generator for generating clock pulse and first and second output signals,said modulator generating an output signal fed to the input of a counter forming part of the compensation circuit and also fed to the input of the impulse shaper,an inverted output of the modulator being connected to the input of the first frequency divider, the inverted output and a non-inverted output of the modulator being connected to first and second sets, respectively, of control terminals of adding circuit control switches in the adding circuit,and the sensor circuit includes a plurality of sensor switches being interconnected to a bridge with the sensor elements in a diagonal between two output terminals of each of said sensor elements, feeding terminals of said sensor elements being parallel-connected and a mains phase terminal being connected to a first input terminal of the bridge through a resistor, whereas a mains zero terminal of said sensor circuit being mass connected.
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Accused Products
Abstract
A wattmeter in which a Hall sensor is provided with a large number of Hall elements, whose voltages are individually tapped. The wattmeter circuit is further provided with an impulse-width modulator, the input voltage of this modulator being periodically reversed, with a feedback to compensate the disturbing voltages, and with a circuit for precision curvature compensation CMOS bandgap reference. The output of an embodiment of the wattmeter is adapted to the reading-off by a computer. A wattmeter can be realized on a semiconductor wafer.
57 Citations
13 Claims
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1. Wattmeter including a Hall sensor circuit and an A/D converter, said Hall sensor including a plurality of Hall elements for producing a plurality of sensor voltages, said A/D converter comprising an impulse-width delta modulator, an impulse shaper, first and second frequency dividers with division ratios N and M, respectively, said frequency dividers connected to said impulse shaper, a compensation circuit for generating a compensation voltage, an adding circuit which receives said plurality of sensor voltages, a reference voltage, and said compensation voltage, a source for producing said reference voltage, said adding circuit producing an output signal fed to the input of said modulator, and a clock generator for generating clock pulse and first and second output signals,
said modulator generating an output signal fed to the input of a counter forming part of the compensation circuit and also fed to the input of the impulse shaper, an inverted output of the modulator being connected to the input of the first frequency divider, the inverted output and a non-inverted output of the modulator being connected to first and second sets, respectively, of control terminals of adding circuit control switches in the adding circuit, and the sensor circuit includes a plurality of sensor switches being interconnected to a bridge with the sensor elements in a diagonal between two output terminals of each of said sensor elements, feeding terminals of said sensor elements being parallel-connected and a mains phase terminal being connected to a first input terminal of the bridge through a resistor, whereas a mains zero terminal of said sensor circuit being mass connected.
Specification