Pressure sensor with on-board compensation
First Claim
1. A pressure sensor, comprising:
- a package substrate including a first side and a second side;
a pressure sensing die mounted relative to the first side of the package substrate, the pressure sensing die including;
a pressure sensing diaphragm;
one or more piezoresistive elements disposed on or adjacent to the pressure sensing diaphragm, wherein the one or more piezoresistive elements have a resistance that varies with an applied pressure to the pressure sensing diaphragm;
a zener diode trim network, wherein the zener diode trim network includes one or more zener diodes and one or more resistive elements, wherein the zener diode trim network is configured to be trimmed to compensate for one or more errors and/or offsets of the pressure sensor;
an on-board heating element, wherein the on-board heating element is configured to heat the pressure sensor when a current is applied to the heater element; and
a housing including a first housing member and a second housing member, the first housing member is mounted on the first side of the package substrate, the second housing member is mounted on the second side of the package substrate, wherein at least one of the first housing member and the second housing member has a pressure port for exposing the pressure sensing diaphragm of the pressure sensing die to a first input pressure.
1 Assignment
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Accused Products
Abstract
The present disclosure relates generally to pressure sensors, and more particularly, to methods and apparatus for compensating pressure sensors for stress, temperature and/or other induced offsets and/or errors. In one illustrative embodiment, a pressure sensor may include a pressure sensing die mounted to a substrate of a pressure sensor package. The pressure sensor die may include on-board compensation. In some instances, the on-board compensation may include an on-board heating element and an on-board zener diode trim network, both situated on or in the pressure sensing die. The zener diode trim network may include one or more zener diodes and one or more resistive elements, where the zener diodes can be selectively activated to “trim” the resistive network to compensate for one or more offsets and/or errors of the pressure sensor. The on-board heating element may be configured to heat the pressure sensor assembly to various temperatures so that temperature related offsets and/or errors may be identified, and then compensated for with the zener diode trim network.
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Citations
20 Claims
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1. A pressure sensor, comprising:
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a package substrate including a first side and a second side; a pressure sensing die mounted relative to the first side of the package substrate, the pressure sensing die including; a pressure sensing diaphragm; one or more piezoresistive elements disposed on or adjacent to the pressure sensing diaphragm, wherein the one or more piezoresistive elements have a resistance that varies with an applied pressure to the pressure sensing diaphragm; a zener diode trim network, wherein the zener diode trim network includes one or more zener diodes and one or more resistive elements, wherein the zener diode trim network is configured to be trimmed to compensate for one or more errors and/or offsets of the pressure sensor; an on-board heating element, wherein the on-board heating element is configured to heat the pressure sensor when a current is applied to the heater element; and a housing including a first housing member and a second housing member, the first housing member is mounted on the first side of the package substrate, the second housing member is mounted on the second side of the package substrate, wherein at least one of the first housing member and the second housing member has a pressure port for exposing the pressure sensing diaphragm of the pressure sensing die to a first input pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A pressure sensor, comprising:
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a pressure sensing die having a front side and a back side, wherein the back side is etched to form a pressure sensing diaphragm; one or more piezoresistive elements disposed on or in the front side of the pressure sensing die on or adjacent to the pressure sensing diaphragm, wherein the one or more piezoresistive elements have a resistance that varies with an applied pressure to the pressure sensing diaphragm; a trim network disposed on the first side of the pressure sensing die, wherein the trim network is configured to compensate for one or more errors and/or offsets in the pressure sensor when the trim network is trimmed, wherein the trim network has a first resistance prior to being trimmed and a second resistance after being trimmed, wherein the second resistance is less than the first resistance; and an on-board heating element, wherein the on-board heating element is configured to heat the pressure sensing die when a current is applied to the heating element. - View Dependent Claims (13, 14, 15, 16)
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17. A method of compensating a pressure sensor for temperature induced errors and/or offsets, the method comprising:
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providing a pressure sensor including a pressure sensing die defining a pressure sensing diaphragm, one or more piezoresistive elements disposed on the pressure sensing die on or adjacent to the pressure sensing diaphragm, a trim network disposed on the pressure sensing die, wherein the trim network is configured to compensate for one or more errors and/or offsets in the pressure sensor when the trim network is trimmed, wherein the trim network has a first resistance, and an on-board heating element, wherein the on-board heating element is configured to heat the pressure sensor when a current is applied; activating the on-board heating element to heat the pressure sensor to a raised temperature; and when the temperature of the pressure sensor reaches the raised temperature, decreasing the resistance of the trim network to a second resistance to compensate for temperature induced errors and/or offsets of the pressure sensor, the second resistance being lower than the first resistance. - View Dependent Claims (18, 19, 20)
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Specification