Measurements in switch devices

Patent metadata

Field	Value
Publication number	US-10365329-B2
Application number	US-201615166075-A
Country	US
Kind code	B2
Filing date	May 26, 2016
Priority date	May 26, 2016
Publication date	Jul 30, 2019
Grant date	Jul 30, 2019

Abstract

Magnetoresistive sensors are used to measure a load current of a switch. In some implementations, additionally a further current sensor may be used. In other implementations, more than one magnetoresistive sensor may be provided.

First claim

What is claimed is:

1. A device comprising:
a switch including a control terminal, a first load terminal, and a second load terminal,
an amplifier,
a magnetoresistive sensor bridge comprising a plurality of magnetoresistive sensors and configured to measure a current flowing between the first load terminal and the second load terminal, wherein a first magnetoresistive sensor of the plurality of magnetoresistive sensors includes a plurality of selectable taps along the first magnetoresistive sensor, and wherein the plurality of selectable taps are switchable to couple to the amplifier, and
a current mirror based sensor to measure the current between the first load terminal and the second load terminal.

2. The device of claim 1 , wherein the plurality of magnetoresistive sensors further comprises a second magnetoresistive sensor, wherein the first magnetoresistive sensor and the second magnetoresistive sensor are configured for different measurement ranges.

3. The device of claim 1 , wherein the plurality of selectable taps are selectable to at least one of controlling an offset of the magnetoresistive sensor bridge, to provide a calibration function, or to provide a fuse function.

4. The device of claim 1 , wherein the switch comprises a switch transistor.

5. The device of claim 1 , wherein the magnetoresistive sensor bridge is based on at least one of a giant magnetoresistance, a tunneling magnetoresistance, a colossal magnetoresistance or an anisotropic magnetoresistance.

6. The device of claim 1 , further comprising an evaluation circuit configured to monitor the switch based on an output of the magnetoresistive sensor bridge.

7. The device of claim 6 , wherein the evaluation circuit is configured to detect an overcurrent based on the output of the magnetoresistive sensor bridge.

8. The device of claim 6 , wherein the evaluation circuit is configured to detect an overtemperature based on an output of the magnetoresistive sensor bridge.

9. The device of claim 6 , wherein the evaluation circuit is configured to detect an aging based on an output of the magnetoresistive sensor bridge.

10. The device of claim 6 , wherein the evaluation circuit is configured to detect at least one of an on-state or an open load.

11. The device of claim 1 , wherein the device is configured to measure a voltage across the switch using the magnetoresistive sensor bridge.

12. The device of claim 1 , wherein the magnetoresistive sensor bridge is provided on a copper clip conducting the current.

13. A method comprising:
providing a switch that comprises a control terminal, a first load terminal, and a second load terminal, and
providing a magnetoresistive sensor bridge comprising a plurality of magnetoresistive sensors to measure a load current through the switch between the first load terminal and the second load terminal,
providing a plurality of selectable taps along a first magnetoresistive sensor of the plurality of magnetoresistive sensors, wherein the plurality of selectable taps are switchable to couple to an amplifier, and
providing a current mirror based sensor to measure the load current through the switch between the first load terminal and the second load terminal.

14. The method of claim 13 , wherein providing the magnetoresistive sensor bridge comprises providing the magnetoresistive sensor bridge with a switchable measurement range.

15. A method comprising:
applying a predetermined current to a switch,
measuring a voltage across the switch using a magnetoresistive sensor bridge comprising a plurality of magnetoresistive sensors, wherein measuring the voltage comprises selecting a tap of a plurality of taps along a first magnetoresistive sensor of the plurality of magnetoresistive sensors, wherein the plurality of selectable taps are switchable to couple to an amplifier, and
determining a drift of at least one of a threshold voltage of the switch or an on resistance of the switch based on the voltage measurement.

16. The method of claim 15 , further comprising monitoring operation of the switch based on an output of the magnetoresistive sensor bridge.

17. The device of claim 1 , wherein the amplifier comprises a differential amplifier including:
a first input node configured to selectively couple to a first tap of the plurality of selectable taps or a second tap of the plurality of selectable taps; and
a second input node coupled to a second node on the magnetoresistive sensor bridge,
wherein the plurality of selectable taps are switchable to couple to the first input node.

18. The device of claim 17 , further comprising an evaluation circuit configured to monitor the switch based on an output of the differential amplifier.

19. The method of claim 15 , wherein the amplifier comprises a differential amplifier, the method further comprising monitoring operation of the switch based on an output of the differential amplifier, wherein the differential amplifier includes:
a first input node selectively coupled to a first tap or a second tap of the plurality of selectable taps; and
a second input node coupled to a second node on the magnetoresistive sensor bridge.

20. A device comprising:
a switch including a control terminal, a first load terminal, and a second load terminal;
a magnetoresistive sensor bridge comprising a first branch connected in parallel with a second branch,
wherein the first branch comprises a first magnetoresistive sensor connected in series with a second magnetoresistive sensor,
wherein second branch comprises a third magnetoresistive sensor connected in series with a fourth magnetoresistive sensor,
wherein the magnetoresistive sensor bridge is configured to measure a current flowing between the first load terminal and the second load terminal,
wherein a first magnetoresistive sensor of the plurality of magnetoresistive sensors includes a plurality of selectable taps along the first magnetoresistive sensor; and
a current mirror based sensor to measure the current between the first load terminal and the second load terminal.

Assignees

• Infineon Technologies Ag

Inventors

• Keser Goran
• Kartal Veli

Classifications

• H03K2217/0027

  Measuring means of, e.g. currents through or voltages across the switch · CPC title

• H03K17/08

  Modifications for protecting switching circuit against overcurrent or overvoltage · CPC title

• G01R31/3277

  of low voltage devices, e.g. domestic or industrial devices, such as motor protections, relays, rotation switches · CPC title

• G01R31/327 Primary

  Testing of circuit interrupters, switches or circuit-breakers · CPC title

• G01R19/16504

  characterised by the components employed · CPC title