Temperature-indicating power adapter and electronic device that operates therewith

• US 6,893,153 B2
• Filed: 06/28/2002
• Issued: 05/17/2005
• Est. Priority Date: 06/28/2002
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Hoffer, Cary J, Bausch, James F
• Primary Examiner(s): Gutierrez, Diego
• Assistant Examiner(s): Jagan, Mirellys
• Application Number:
  US10/187,189
• Publication Number:
  US 20040001526A1
• Time in Patent Office: 1,054 Days
• Field of Search: 374/141, 374/162, 374/152, 374/159, 374/183, 374/185, 374/208, 116/207
• US Class Current: 374/152
• CPC Class Codes: G01K 13/00 Thermometers specially adapted for specific purposes

Abstract

A temperature-indicating power adapter includes a case, a conversion module coupled to the case that receives a first voltage and produces a second voltage. The adapter also includes a temperature-indicating device that is also coupled to the case for indicating the temperature of the case.

Claims

1. A temperature-indicating power adapter comprising:

a case;

a conversion module coupled to the case that receives a first voltage and produces a second voltage, the case dissipating at least some of the heat generated by the conversion module;

a temperature-indicating device also coupled to the case for indicating the temperature of the case, wherein the temperature of the case increases due to the heat produced from a conversion of the first voltage into the second voltage;

wherein the temperature-indicating device comprises;

a temperature sensitive resistor that changes resistivity in response to a change in the temperature of the case;

a comparator coupled to the temperature sensitive resistor and configured to generate an output based upon the resistivity of the temperature sensitive resistor;

a diode;

a transistor coupled to the diode and the comparator, the transistor configured to switch a state of the diode based upon the output of the comparator;

a second diode; and

a second transistor coupled to the second diode and the comparator, the second transistor configured to switch a state of the second diode based upon the output of the comparator, wherein the second diode has a state that is opposite to the state of the other diode.

2. The temperature-indicating power adapter of claim 1, wherein the temperature-indicating device presents a first visual indication for case temperatures within a first temperature range and a second visual indication for case temperatures within a second temperature range.

3. The temperature-indicating power adapter of claim 1, wherein the first voltage is conveyed to the temperature-indicating power adapter using an alternating current and wherein the second voltage is conveyed from the power adapter using a direct current.

4. The power adapter of claim 1, further comprising a switch coupled to the temperature-indicating device, the switch interrupting current produced at the second voltage by the conversion module.

5. The power adapter of claim 1, further comprising:

a switch coupled to the temperature-indicating device, where the switch interrupts current associated with the second voltage if the temperature of the case increases beyond a predetermined amount.

6. The temperature-indicating power adapter of claim 1, wherein the temperature-indicating device produces a visual indication of the temperature of the case.

7. The temperature-indicating power adapter of claim 6, wherein the temperature-indicating device includes at least one light-emitting diode.

8. A temperature-indicating power adapter comprising:

means for converting an alternating current voltage input to a direct current output;

means for housing the means for converting;

means for visually indicating the temperature of the means for housing the means for converting, wherein the means for housing the means for converting dissipates at least some of the heat generated by the means for converting and wherein the temperature of the means for housing increases due to the heat produced from a conversion of the alternating current voltage input into the direct current output;

wherein the means for visually indicating the temperature comprises;

a temperature sensitive resistor that changes resistivity in response to a change in the temperature of the means for housing;

a comparator coupled to the temperature sensitive resistor and configured to generate an output based upon the resistivity of the temperature sensitive resistor;

a first diode;

a transistor coupled to the first diode and the comparator, the transistor configured to switch a state of the first diode based upon the output of the comparator;

a second diode; and

a second transistor coupled to the second diode and the comparator, the second transistor configured to switch a state of the second diode based upon the output of the comparator, wherein the second diode has a state that is opposite to the state of the first diode.

9. The temperature-indicating power adapter of claim 8, further comprising means for interrupting the direct current output, the means for interrupting the direct current output being coupled to the means for visually indicating the temperature.

10. The temperature-indicating power adapter of claim 8, wherein the means for visually indicating the temperature comprises:

switching means for interrupting the direct current output if the temperature of the means for housing increases beyond a predetermined amount.

11. The temperature-indicating power adapter of claim 8, wherein the first diode includes a light source that indicates that the temperature of the housing is below a predetermined value.

12. The temperature-indicating power adapter of claim 11, wherein the second diode includes a second light source that indicates that the temperature of the housing is above the predetermined value.

13. The temperature-indicating power adapter of claim 8, wherein the temperature sensitive resistor a coupled to a portion of the means for housing the means for converting, the temperature sensitive resistor undergoing a change in resistivity as the portion of the means for housing changes in temperature.

14. The temperature-indicating power adapter of claim 13, wherein the temperature sensitive resistor reduces resistivity as the portion of the housing increases in temperature.

15. The temperature-indicating power adapter of claim 13, wherein the temperature sensitive resistor increases resistivity as the portion of the means for housing increases in temperature.