Switch detection device and method of use

Patent metadata

Field	Value
Publication number	US-9329237-B2
Application number	US-201414152262-A
Country	US
Kind code	B2
Filing date	Jan 10, 2014
Priority date	Jan 10, 2014
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

A method of switch detection is disclosed that comprises, enabling a low power mode on a switch detection device, activating a first detection circuit for detecting, at a first expiration of a first polling time interval, a first switch state of a first switch having a first priority level, the first switch state including one of a first open state and a first closed state, comparing the detected first switch state with a prior first switch state, and activating a second detection circuit for detecting, at a second expiration of a second polling time interval, a second switch state of a second switch having a second priority level, the second switch including one of a second open state and a second closed state, and the second polling time interval being greater than the first polling time interval, and the second priority level being different from the first priority level.

First claim

What is claimed is:

1. A method of switch for saving electrical power, the method comprising:
enabling a low power mode on a switch detection device;
activating a first detection circuit for detecting a first switch state of a first switch having a first priority level, defined by a first polling time interval, wherein the detecting of the first switch state is performed at a first expiration of the first polling time interval, and wherein the first switch state includes one of a first open state and a first closed state;
comparing the detected first switch state with a prior first switch state;
activating a second detection circuit for detecting a second switch state of a second switch having a second priority level defined by a second polling time interval, wherein the detecting of the second switch state is performed at a second expiration of the second polling time interval, wherein the second switch includes one of a second open state and a second closed state, wherein the second polling time interval is greater than the first polling time interval to save electrical power;
comparing the detected second switch state with a prior second switch state; and
outputting a wake signal if at least one of the detected first switch state and detected second switch state differs from its respective prior switch state.

2. The method of claim 1 , wherein activating the first detection circuit includes activating a first current source to provide a first current to a first switch circuit, wherein the first switch circuit is in communication with the first switch; wherein activating the second detection circuit includes activating a second current source to provide a second current to a second switch circuit, wherein the second switch circuit is in communication with the second switch; wherein the first switch is configured to change states when a vehicle is in a non-operational mode, and wherein the second switch is less likely than the first switch to change states when the vehicle is in the non-operational mode.

3. The method of claim 2 , wherein activating the first detection circuit includes activating a first detector, associated with the first switch circuit, to measure a first voltage received at a first detector input, wherein the first voltage is received from the first switch circuit; and wherein activating the second detection circuit includes activating a second detector, associated with the second switch circuit, to measure a second voltage received at a second detector input, wherein the second voltage is received from the second switch circuit.

4. The method of claim 3 , wherein the detecting of the first switch state includes detecting if the first voltage measured at the first detector input has reached a preselected first threshold voltage and providing a first signal at a first detector output if the preselected first threshold voltage is reached and a second signal at the first detector output if the preselected first threshold voltage is not reached; and wherein the detecting of the second switch state includes detecting if the second voltage measured at the second detector input has reached a preselected second threshold voltage and providing a first signal at a second detector output if the preselected second threshold voltage is reached and a second signal at the second detector output if the preselected second threshold voltage is not reached.

5. The method of claim 4 , wherein the first threshold voltage was selected from a plurality of configurable threshold voltages and the second threshold voltage was selected from at least one of the plurality of configurable threshold voltages and an additional plurality of configurable threshold voltages, and wherein the selected second threshold voltage is not equal to the selected first threshold voltage.

6. The method of claim 3 , wherein comparing the detected first switch state with the prior first switch state includes receiving a first detector output at an interface control unit and comparing the first detector output with the prior first switch state stored in a first register in the interface control unit; and wherein comparing the detected second switch state with the prior second switch state includes receiving a second detector output at an interface control unit and comparing the second detector output with the prior second switch state stored in a second register in the interface control unit.

7. The method of claim 1 , further including deactivating the first detection circuit after comparing the detected first switch state with a prior first switch state; and deactivating the second detection circuit after comparing the detected second switch state with a prior second switch state.

8. The method of claim 1 , further including:
activating a third detection circuit for detecting, at a third expiration of a third polling time interval, a third switch state of a third switch having a third priority level, wherein the third switch state includes one of a third open state and a third closed state.

9. The method of claim 8 , further including:
activating a third detector associated with the third switch circuit, to monitor a third voltage detected at a third detector input, wherein the third voltage is received from the third switch circuit;
providing a determination of the third switch state by detecting if the third voltage at the third detector input is below a third threshold voltage;
comparing the detected third switch state with a prior third switch state; and
outputting a wake signal if the third switch state has changed.

10. A switch detection device for saving electrical power, the device comprising:
a clock, configured to be monitored for a plurality of polling time intervals including a first polling time interval defining a first priority level and a second polling time interval defining a second priority level, wherein the second polling time interval is greater than the first polling time interval for saving electrical power;
a first detection circuit configured for interconnection with a first switch and for detecting a first switch state that includes one of an open state or a closed state;
a second detection circuit configured for interconnection with a second switch and for detecting a second switch state that includes one of an open state or a closed state; and
an interface control unit in communication with the first detection circuit and second detection circuit, for activating the first detection circuit at the expiration of the first polling time interval, and for activating the second detection circuit at the expiration of the second polling time interval.

11. The device of claim 10 , wherein the interface control unit is configured to receive and compare the detected first switch state with a stored prior first switch state, wherein the interface control unit is configured to receive and compare the detected second switch state with a stored prior second switch state, wherein the first switch is configured to change states when a vehicle is in a non-operational mode, and wherein the second switch is less likely than the first switch to change states when the vehicle is in the non-operational mode.

12. The device of claim 11 , further including an output port configured to provide an external wake signal if at least one of the first switch state and second switch state is determined to differ from its respective prior switch state.

13. The device of claim 11 , further including a third detection circuit having a third detector in communication with a third switch circuit and configurable to compare a third measured voltage receivable at a third detector input with a

Assignees

• Freescale Semiconductor Inc

Inventors

• Edwards William E
• Andresen Anthony F
• Gray Randall C

Classifications

• G01R31/327 Primary

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

• H03K17/18 Primary

  Modifications for indicating state of switch · CPC title