Power calculating device
First Claim
1. A power calculating device, comprising:
- control signal generating means for generating a control signal determining a power calculating period and an imbalance compensation period;
input voltage changeover means which receives a first voltage corresponding to a voltage of a system under measurement and said control signal for changing over between said first voltage and a constant voltage under the control of said control signal to generate a second voltage;
said second voltage being said first voltage during said power calculating period and said constant voltage during said imbalance compensation period;
a Hall element member which receives a current corresponding to said second voltage for flowing said current in said Hall element member between current terminals thereof to generate a third voltage corresponding to a product of said second voltage and a magnetic density generated by a magnetic field applied to said Hall element member;
imbalance detecting means which receives said control signal and said third voltage for detecting an offset of said Hall element member based on said third voltage when said control signal shows said imbalance compensation period to generate an offset compensation signal corresponding to said offset;
variable resistor means connected to said Hall element member and which receives said offset compensation signal, a resistance value thereof being changed by said offset compensation signal; and
power value outputting means which receives said third voltage and said control signal for outputting said third voltage when said control signal shows said power calculating period as an output of said power calculating device corresponding to a power of said system under measurement;
whereby an imbalance voltage of said Hall element member being compensated.
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Accused Products
Abstract
A power calculating device including a control signal generating unit for generating a control signal. The control signal determines a power calculating period and an imbalance compensation period. The device also includes an input voltage changeover unit for changing over between a first voltage corresponding to a voltage of a system under measurement and a constant voltage under the control of the control signal to generate a second voltage, which is the first voltage during the power calculating period and the constant voltage during the imbalance compensation period. The device further includes a Hall element member for generating a third voltage corresponding to a product of the second voltage and a magnetic density generated by a magnetic field applied to the Hall element member. The device also includes an imbalance detecting unit for generating an offset compensation signal based on the third voltage, and a variable resistor connected to the Hall element member. The resistance value thereof is changed by the offset compensation signal, whereby an imbalance voltage of the Hall element member is compensated.
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Citations
13 Claims
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1. A power calculating device, comprising:
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control signal generating means for generating a control signal determining a power calculating period and an imbalance compensation period; input voltage changeover means which receives a first voltage corresponding to a voltage of a system under measurement and said control signal for changing over between said first voltage and a constant voltage under the control of said control signal to generate a second voltage; said second voltage being said first voltage during said power calculating period and said constant voltage during said imbalance compensation period; a Hall element member which receives a current corresponding to said second voltage for flowing said current in said Hall element member between current terminals thereof to generate a third voltage corresponding to a product of said second voltage and a magnetic density generated by a magnetic field applied to said Hall element member; imbalance detecting means which receives said control signal and said third voltage for detecting an offset of said Hall element member based on said third voltage when said control signal shows said imbalance compensation period to generate an offset compensation signal corresponding to said offset; variable resistor means connected to said Hall element member and which receives said offset compensation signal, a resistance value thereof being changed by said offset compensation signal; and power value outputting means which receives said third voltage and said control signal for outputting said third voltage when said control signal shows said power calculating period as an output of said power calculating device corresponding to a power of said system under measurement; whereby an imbalance voltage of said Hall element member being compensated. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification