Voltage measuring instrument with flying capacitor
First Claim
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1. A voltage measuring apparatus comprising:
- (N+1) voltage detection terminals connected to N series connected voltage sources wherein N is an integer;
a capacitor;
a first multiplexer for selectively connecting odd-numbered ones of the voltage detection terminals to one terminal of the capacitor;
a second multiplexer for selectively connecting even-numbered ones of the voltage detection terminals to the other terminal of the capacitor;
wherein the second multiplexer and the first multiplexer act as a first switching device;
a buffer circuit;
a second switching device for connecting both terminals of the capacitor to the buffer circuit; and
, a polarity corrector for making voltages from odd-numbered ones of the voltage sources the same in polarity as voltages from even-numbered ones of the voltage sources.
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Abstract
The voltage measuring apparatus of the present invention comprises: a capacitor configured of a plurality of capacitor elements and divided at a connection point into two sections of the same capacitance; a first switching device for connecting a voltage source to be measured to both terminals of the capacitor; a differential amplifier; a second switching device for connecting both terminals of the capacitor to inputs of the differential amplifier; and a third switch for connecting the connection point in the capacitor to signal reference potential of the differential amplifier in time synchronization with the second switching device.
92 Citations
11 Claims
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1. A voltage measuring apparatus comprising:
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(N+1) voltage detection terminals connected to N series connected voltage sources wherein N is an integer;
a capacitor;
a first multiplexer for selectively connecting odd-numbered ones of the voltage detection terminals to one terminal of the capacitor;
a second multiplexer for selectively connecting even-numbered ones of the voltage detection terminals to the other terminal of the capacitor;
wherein the second multiplexer and the first multiplexer act as a first switching device;
a buffer circuit;
a second switching device for connecting both terminals of the capacitor to the buffer circuit; and
,a polarity corrector for making voltages from odd-numbered ones of the voltage sources the same in polarity as voltages from even-numbered ones of the voltage sources. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
the voltage measuring apparatus further includes a differential amplifier connected to the second switching device, and a third switch for connecting the connection point in the capacitor to a signal reference potential of the differential amplifier in time synchronization with the second switching device. -
8. A voltage measuring apparatus according to claim 7, wherein a pair of switched that are synchronized in time with the first and second multiplexers are provided between the capacitor and the first and second multiplexers.
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9. A voltage measuring apparatus according to claim 1, further comprising a voltage divider for resistive-dividing the voltage appearing at both ends of the series connection of the N voltage sources, and a multiplexer for taking therein an output voltage of the voltage divider.
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10. A voltage measuring apparatus according to claim 9, wherein a switch is provided between the voltage sources and the voltage divider.
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11. A voltage measuring apparatus according to claim 1, wherein a resistor is provided between the capacitor and the multiplexers.
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Specification