APPARATUS, SYSTEM AND METHOD FOR IDENTIFICATION WITH TEMPERATURE DEPENDENT RESISTIVE DEVICE

• US 20080079446A1
• Filed: 09/07/2006
• Published: 04/03/2008
• Est. Priority Date: 09/07/2006
• Status: Active Grant

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Wireless Corporation (Kyocera Corporation)
• Inventors: TAYLOR, John Philip
• Granted Patent: US 7,508,225 B2
• Time in Patent Office: Days
• US Class Current: 324/721
• CPC Class Codes: G01K 1/026 arrangements for monitoring a plurality of temperatures, e.g. by multiplexing
• CPC Class Codes: G01K 7/16 using resistive elements resistive elements per se H01C, H01L

Abstract

An apparatus, system, and method provide device identification and temperature sensing of a device with a temperature sensing circuit (TSC) within the device. The TSC includes a temperature sensing element (TSE) connected in parallel with a voltage clamping network (VCN) that limits the voltage across the TSE to an identification voltage within an identification voltage range when the voltage is greater than or equal to a lower voltage of the identification voltage range. When a voltage below the lower range is applied to the TSC, the VCN appears as an open circuit and the resistance of the TSC corresponds to temperature. For cost or other concerns, a first TSC may omit the VCN to provide a maximum identification voltage and other TSCs may include VCNs with lower identification voltage ranges.

Claims

1. A temperature sensing circuit comprising:

a temperature sensing element; and

a voltage clamping network connected in parallel to the temperature sensing element, the voltage clamping network configured to limit a voltage across the voltage clamping network to an identification voltage range when the voltage is greater than or equal to a lower voltage of the identification voltage range.

2. The temperature sensing circuit of claim 1, wherein the voltage clamping network comprises a diode arrangement.

3. The temperature sensing circuit of claim 2, wherein the diode arrangement comprises a Zener diode.

4. The temperature sensing circuit of claim 2, wherein the diode arrangement comprises a plurality of diodes connected in series.

5. The temperature sensing circuit of claim 2, wherein the diode arrangement comprises an active Zener diode.

6. The temperature sensing circuit of claim 5, wherein the active Zener diode is one of a plurality of active zener devices configured to provide one of a plurality of clamping voltages.

7. The temperature sensing circuit of claim 2, wherein the voltage clamping network comprises an identification resistor connected in series with the diode arrangement.

8. The temperature sensing circuit of claim 7, wherein the identification resistor is one of a set of identification resistors, each identification resistor corresponding to one of a plurality of identification voltage ranges.

9. A temperature measuring and identification (TMID) device comprising:

a voltage source connected to a detection port through a limiting resistor;

a current source connected to the detection port; and

a controller configured to identify a temperature measuring circuit connected to the detection port from a plurality of temperature measuring circuits based on a first measured voltage at the detection port when the voltage source provides an output voltage resulting in a first measured voltage above an upper voltage of a temperature measuring voltage range and configured to determine a temperature of the temperature sensing circuit based on a second measured voltage at the detection port when the voltage source is off.

10. The TMID device of claim 9, wherein the current source comprises a bias resistor connected to a supply voltage, the bias resistor connected in series with the temperature sensing element when the identification device is connected to the detection port.

11. The TMID device of claim 9, the voltage source comprising a general purpose input/output (GPIO) port of a processor, the GPIO port providing the output voltage in an output state and providing an open circuit when the GPIO is an off state.

12. The TMID device of claim 11, further comprising:

an analog to digital converter (ADC) connected to the detection port and configured to provide a first digital value corresponding to the first measured voltage and a second digital value corresponding to the second measured voltage.

13. The TMID device of claim 12, the controller configured to determine that the temperature measuring circuit has a first identification value when the first measured voltage is within a first identification voltage range and to determine that the temperature circuit has a second identification value when the first measured temperature is within a second identification voltage range.

14. The TMID device of claim 12, wherein the first measured voltage is equal to a voltage clamp voltage within a clamp voltage range of a voltage clamp circuit connected in parallel to a temperature sensing element within the temperature measuring circuit.

15. A device identification system comprising:

a plurality of temperature sensing circuits, at least some of the temperature sensing circuits comprising a temperature sensing element and a voltage clamping network connected in parallel to the temperature sensing element, the voltage clamping network configured to limit a voltage at a connector to an identification voltage range when the voltage is greater than or equal to a lower voltage of the identification voltage range; and

a temperature measuring and identification (TMID) device having a detection port configured to connect the connector of each of the plurality of temperature sensing circuits, the TMID device comprising;

a voltage source connected to a detection port through a limiting resistor;

a current source connected to the detection port; and

a controller configured to identify a connected temperature measuring circuit connected to the detection port from the plurality of temperature measuring circuits based on a first measured voltage at the detection port when the voltage source provides an output voltage resulting in a first measured voltage above an upper voltage of a temperature measuring voltage range and configured to determine a temperature of the connected temperature sensing circuit based on a second measured voltage at the detection port when the voltage source is off.

16. The identification system of claim 15, wherein the plurality of temperature sensing circuits comprises a first set of temperature sensing circuits corresponding to a first identification value and a second set of temperature sensing circuits corresponding to a second identification value.

17. The identification system of claim 16, wherein each of the temperature sensing circuits of the first set comprises the temperature sensing element and wherein each of the temperature sensing circuits of the second set comprises the temperature sensing element and a second set voltage clamping network connected in parallel to the temperature sensing element, the second set voltage clamping network configured to limit the voltage at the connector to a second set identification voltage range when the voltage is greater than or equal to a lower voltage of the second set identification voltage range.

18. The identification system of claim 17, wherein the plurality of temperature sensing circuits further comprises a third set of temperature sensing circuits corresponding to a third identification value.

19. The identification system of claim 18, wherein each of the temperature sensing circuits of the third set comprises the temperature sensing element and a third set voltage clamping network connected in parallel to the temperature sensing element, the third set voltage clamping network configured to limit the voltage at the connector to a third set identification voltage range when the voltage is greater than or equal to a lower voltage of the third identification voltage range, the third set voltage clamping network comprising a voltage clamping device connected in series with an identification resistor.

20. The identification system of claim 19, wherein the plurality of temperature sensing circuits further comprises a fourth set of temperature sensing circuits corresponding to a fourth identification value, each of the temperature sensing circuits of the fourth set comprising the temperature sensing element and a fourth set voltage clamping network connected in parallel to the temperature sensing element, the fourth set voltage clamping network configured to limit the voltage at the connector to a third set identification voltage range when the voltage is greater than or equal to a lower voltage of the third identification voltage range, the fourth set voltage clamping network comprising the voltage clamping device connected in series with another identification resistor.