Digital output MEMS pressure sensor and method

• US 20050109115A1
• Filed: 09/28/2004
• Published: 05/26/2005
• Est. Priority Date: 11/20/2003
• Status: Active Grant

• Current Assignee: Gary G. Gatesman
• Original Assignee: Gary G. Gatesman
• Inventors: Gatesman, Gary G.
• Granted Patent: US 7,194,910 B2
• Time in Patent Office: Days
• US Class Current: 73/753
• CPC Class Codes: G01L 9/125 with temperature compensating means non electric temperature compensating means G01L19/04
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/15311 being a ball array, e.g. BGA

Abstract

A method and pressure-sensor system provide a digital-frequency output linearly proportional to a sensed pressure. The system comprises a MEMS pressure-sensing element to provide a pressure-sensing output and voltage-to-frequency converter provide the digital-frequency output. The pressure-sensor system may also comprise an amplifier to provide an output voltage linearly proportional to the pressure. A temperature sensor and temperature-compensation circuitry provide a temperature-compensation signal to the amplifier to at least partially offset the effects of temperature on the system. Some embodiments of the present invention comprise a microcontroller system comprising a microcontroller and an RF transmitter. The microcontroller may receive the digital-frequency output and may generate a notification signal when the sensed pressure is inside or outside a predetermined pressure range. The RF transmitter may transmit an RF signal to indicate that the sensed pressure is inside or outside the predetermined pressure range.

Claims

1. A product pressure-monitoring system comprising:

a pressure-sensing system comprising a pressure-sensing element to provide a pressure-sensing output proportional to a sensed pressure; and

a voltage-to-frequency converter provide a digital-frequency output linearly proportional to the sensed pressure; and

a microcontroller system comprising a microcontroller and an RF transmitter, the microcontroller to receive the digital-frequency output, wherein the microcontroller generates a notification signal when the sensed pressure is either inside or outside a predetermined pressure range, and the RF transmitter is to transmit an RF signal in response to the notification signal, the RF signal indicating that the sensed pressure is either inside or outside the predetermined pressure range.

2. The system of claim 1 wherein the microcontroller system and pressure-sensor system are located on a single circuit board.

3. The system of claim 1 wherein the microcontroller system and pressure-sensor system are fabricated on a single monolithic semiconductor die.

4. The system of claim 2 further comprising an RF antenna to transmit the RF signal.

5. The system of claim 4 wherein the pressure-sensing system further comprises:

an amplifier to amplify the pressure-sensing output and provide an output voltage linearly proportional to the voltage-to-frequency converter;

a temperature sensor; and

temperature-compensation circuitry responsive to the temperature sensor to provide a temperature-compensation signal to the amplifier, wherein the temperature-compensation circuitry is to at least in part offset temperature effects on the system.

6. The system of claim 4, wherein the pressure-sensor system further comprises:

a package; and

a semiconductor die mounted within the package, the semiconductor die including the pressure-sensing element.

7. The system of claim 6 further comprising a lid on the package allowing either a gas or a fluid into the package, wherein the sensed pressure is to deform the die, and the pressure-sensing element is to provide one of either a capacitive or resistive output in response to the deformation of the die;

and a silicone gel coating within a cavity of the package, the gel coating at least covering the die.

8. The system of claim 6 wherein the system is a tire pressure-monitoring system, and wherein pressure-sensing system and microcontroller system are to receive power from a battery.