What is claimed is:
1. A semiconductor pressure sensor comprising:
a semiconductor substrate having a principle surface corresponding to (110)-face;
a pressure detecting diaphragm formed on the principle surface of the semiconductor substrate; and
strain gage resistors formed on the diaphragm for constituting a bridge circuit and outputting a detection signal in connection with strain of the diaphragm,
wherein the pressure detecting diaphragm has a planar shape comprised of four sides, the fours sides including a pair of first sides extending along <110> crystal axis direction and a pair of second sides extending along <100> crystal axis direction,
wherein the strain gage resistors comprise a pair of center gages disposed at a center portion of the pressure detecting diaphragm along the <110> crystal axis direction and a pair of side gages disposed be nearer to a peripheral portion of the pressure detecting diaphragm than the center gages so both of the pair of side gages are disposed at a portion of the semiconductor substrate having approximately a same stress distribution.
2. The semiconductor pressure sensor according to claim 1, wherein when an axis bisecting each of the first sides of the diaphragm and passing through the center point of the diaphragm is set as a first axis and an axis vertically-intersecting to the first axis and passing through the center point of the diaphragm is set as a second axis, wherein each of the side gages is located on a virtual line which extends from the center point of each of the center gages to the peripheral portion of the diaphragm and intersects to the first axis and the second axis at 45.
3. The semiconductor pressure sensor according to claim 2, wherein the pair of side gages are arranged to be positionally symmetrical with each other with respect to the first axis.
4. The semiconductor pressure sensor according to claim 3, wherein the pair of side gages are arranged to be positionally symmetrical with each other with respect to the second axis.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of measuring a battery power, the method comprising:
a) detecting a voltage and a temperature at an output terminal of a battery;
b) obtaining a first correction coefficient based on a battery open-circuit voltage at a previous sample time;
c) obtaining a second correction coefficient based on said battery temperature;
d) calculating a real-time battery open-circuit voltage by using said voltage at said output terminal of said battery, said first and second correction coefficients, said battery open-circuit voltage at said previous sample time, and a time interval between said previous sample time and a present sample time; and
e) converting said real-time battery open-circuit voltage into a battery power measurement for display.
2. The method of claim 1, further comprising:
a) determining if said battery is in a relaxed state based on a changing rate of said real-time battery open-circuit voltage; and
b) setting said real-time battery open-circuit voltage to be equal to said voltage at said output terminal of said battery when said battery is in said relaxed state.
3. The method of claim 1, further comprising storing said real-time battery open-circuit voltage for calculating a subsequent battery open-circuit voltage.
4. The method of claim 1, further comprising:
a) detecting said battery; and
b) determining a relationship between said battery open-circuit voltage and said battery power measurement.
5. The method of claim 1, further comprising:
a) detecting said battery;
b) determining a relationship between said first correction coefficient and said battery open-circuit voltage; and
c) determining a relationship between said second correction coefficient and said battery temperature.
6. A battery power measuring device, comprising:
a) a detection device configured to detect a voltage and a temperature at an output terminal of a battery;
b) a storage device configured to store a first correction coefficient corresponding to a battery open-circuit voltage at a previous sample time, and a second correction coefficient corresponding to said temperature;
c) a calculation device configured to calculate a real-time battery open-circuit voltage based on said voltage at said output terminal of said battery, said first and second correction coefficients, said battery open-circuit voltage at said previous sample time, and a time interval between said previous sample time and a present sample time; and
d) a display device configured to convert said real-time battery open-circuit voltage to a battery power measurement for display.
7. The battery power measuring device of claim 6, further comprising a calibration circuit configured to determine if said battery is in a relaxed state based on a changing rate of said real-time battery open-circuit voltage, and to set said real-time battery open-circuit voltage to be equal to said voltage at said output terminal of said battery when said battery is in said relaxed state.
8. The battery power measuring device of claim 6, wherein said storage device is configured to store said real-time battery open-circuit voltage to calculate a subsequent battery open-circuit voltage.
9. The battery power measuring device of claim 6, wherein said storage device is configured to store data characterizing a relationship between said real-time battery open-circuit voltage and said battery power measurement.
10. The battery power measuring device of claim 6, wherein said storage device is configured to store:
a) data characterizing a relationship between said real-time battery open-circuit voltage and said first correction coefficient; and
b) data characterizing a relationship between said temperature and said second correction coefficient.
11. An apparatus, comprising:
a) said battery power measuring device of claim 6;
b) a charging power supply configured to charge said battery; and
c) electrical equipment configured to receive power from said battery.