SYSTEMS AND METHODS FOR HIGH VOLTAGE BRIDGE BIAS GENERATION AND LOW VOLTAGE READOUT CIRCUITRY

• US 20150316586A1
• Filed: 04/30/2014
• Published: 11/05/2015
• Est. Priority Date: 04/30/2014
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Hammerschmidt, Dirk, Bogner, Peter, Astrom, David
• Granted Patent: US 9,921,249 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01D 3/036 on measuring arrangements themselves
• CPC Class Codes: G01L 9/12 by making use of variations in capacitance , i.e. electric circuits therefor
• CPC Class Codes: G01R 17/06 Automatic balancing arrangements
• CPC Class Codes: G01R 19/0084 measuring voltage only all subgroups of G01R19/00 take precedence
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps

Abstract

A multi voltage sensor system includes one or more charge pumps, a sensor bridge and readout circuitry. The one or more charge pumps are configured to provide a high voltage. The sensor bridge is biased by the high voltage and is configured to provide sensor values. The readout circuitry includes only low voltage components. The readout circuitry is configured to receive the sensor values.

Claims

1. A multi voltage sensor system comprising:

one or more charge pumps configured to provide a high voltage;

a sensor bridge biased by the high voltage and configured to provide sensor values; and

low voltage readout circuitry having only low voltage components and configured to receive the sensor values.

2. The system of claim 1, further comprising a low voltage regulator configured to generate a low voltage and to provide the low voltage to the readout circuitry.

3. The system of claim 1, further comprising a medium voltage regulator configured to generate a medium voltage and to provide the medium voltage to the one or more charge pumps.

4. The system of claim 1, wherein the one or more charge pumps include a positive charge pump and a negative charge pump.

5. The system of claim 4, wherein the sensor bridge includes polarity reverting switches, wherein the positive charge pump supplies a positive high voltage to the sensor bridge and the negative charge pump supplies a negative high voltage to the sensor bridge, and wherein the polarity reverting switches alternate between the positive high voltage and the negative high voltage.

6. The system of claim 1, wherein the sensor bridge is operated in a force feedback loop.

7. The system of claim 1, wherein the sensor bridge includes a deflectable membrane configured to provide a capacitance according to an amount of deflection.

8. The system of claim 1, wherein the sensor bridge includes a pair of deflectable membranes and a pair of reference capacitors, which are configured as a bridge.

9. The system of claim 1, wherein the high voltage is adjusted by an amount to enhance operation of the sensor bridge.

10. The system of claim 1, further comprising a level shifter configured to lower the voltage level of the sensor values.

11. The system of claim 1, further comprising pump control circuitry configured to activate and deactivate the one or more charge pumps according to a charging phase, a controlled discharge phase, and a measurement phase for each clock cycle.

12. The system of claim 1, wherein the low voltage readout circuitry includes a switched capacitor level shifter having cross coupled switches.

13. A system for controlling a charge pump, the system comprising:

a charging comparator configured to deactivate a charge pump upon a measurement sensor having a voltage exceeding a charging threshold;

a discharging comparator configured to stop discharging the measurement sensor upon the measurement sensor having a voltage at a discharging threshold; and

a current control device configured to control a discharge current for the measurement sensor.

14. The system of claim 13, further comprising a switch configured to disconnect the current control device from the measurement sensor according to a signal generated by the discharging comparator.

15. The system of claim 13, wherein the discharging threshold is set to a mid point voltage.

16. The system of claim 15, wherein the charging threshold is set to the mid point voltage plus a delta amount.

17. The system of claim 15, wherein the mid point voltage is assigned using a reference current and a resistor.

18. The system of claim 15, wherein the discharge current is led through a resistor and shifts a voltage of the charge pump.

19. The system of claim 13, wherein the system includes a charging phase, a discharging phase, and a measurement phase, wherein the charging phase ends on the measurement sensor having a voltage exceeding the charging threshold and the discharging phase ends on the measurement sensor having a voltage at the discharging threshold.

20. A method for reading a high voltage sensor with low voltage circuitry, the method comprising:

providing a sensor bridge;

biasing the sensor bridge with one or more charge pump voltages;

providing sensor values from the bridge at a low voltage level; and

measuring the sensor values using only low voltage readout circuitry.

21. The method of claim 20, further comprising generating the one or more charge pump voltages about a mid point voltage.

22. The method of claim 20, wherein the low voltage readout circuitry operates at less than 2 volts.