Fan operation detection

Patent metadata

Field	Value
Publication number	US-9982680-B2
Application number	US-201315029934-A
Country	US
Kind code	B2
Filing date	Oct 23, 2013
Priority date	Oct 23, 2013
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

Inputting an input resistance to an operational amplifier. Detecting whether a number of fans are in operation based on the input resistance to the operational amplifier by driving a number of resistors connected in series in a fan circuit associated with the number of fans.

First claim

What is claimed:

1. A circuit for fan operation detection, comprising:
an operational amplifier having an output to drive a resistor of a fan, the resistor of the fan in series with a transistor of the fan, and the operational amplifier having an input connected to an input resistance that includes the resistor of the fan, the operational amplifier to detect an operation of the fan based on the input resistance.

2. The circuit of claim 1 , wherein the input of the operational amplifier is connected to the resistor of the fan.

3. The circuit of claim 1 , wherein the input resistance that is input to the operational amplifier is based on a plurality of resistors associated with a plurality of fans.

4. The circuit of claim 3 , wherein a change in the input resistance changes a gain of the operational amplifier.

5. The circuit of claim 4 , wherein the gain of the operational amplifier determines an output voltage of the output of the operational amplifier relative to a voltage reference connected to another input of the operational amplifier.

6. A method for fan operation detection, comprising:
driving fault resistors of a plurality of fans with an output of an operational amplifier;
inputting an input resistance based on the fault resistors to an input of the operational amplifier; and
comparing a voltage reference to an output voltage of the output of the operational amplifier.

7. The method of claim 6 , comprising detecting a number of the plurality of fans that are operating based on the comparing.

8. The method of claim 7 , wherein detecting the number of the plurality of fans that are operating comprises detecting a greater number of operating fans with a decrease in the input resistance and an increase in the output voltage of the operational amplifier.

9. The method of claim 6 , comprising increasing a gain of the operational amplifier in response to a decrease in the input resistance.

10. The method of claim 9 , comprising increasing the output voltage of the output of the operational amplifier relative to the voltage reference in response to increasing the gain of the operational amplifier.

11. A system comprising:
a plurality of fans coupled to an operational amplifier, wherein each of the plurality of fans comprises a circuit including a resistor in series with a transistor; and
an operational amplifier to:
drive the resistor of each of the plurality of fans; and
detect whether each of the plurality of fans is operating based on an input resistance to the amplifier operational using a voltage reference.

12. The system of claim 11 , further comprising a processor to detect a number of the plurality of fans that are operating by comparing the voltage reference to an output of the operational amplifier.

13. The system of claim 11 , wherein the plurality of fans are coupled to an input of the operational amplifier, wherein the input includes the input resistance that is based on the resistors of the plurality of fans.

14. The system of claim 11 , wherein an output of the operational amplifier is to drive each of the resistors of the plurality of fans.

15. The system of claim 14 , wherein the operational amplifier is to provide a flow of current that drives each of the resistors of the plurality of fans.

16. The system of claim 15 , wherein the operational amplifier is to provide the flow of current to the resistors of the plurality of fans over a signal path connected to the resistors of the plurality of fans, and wherein the signal path is further connected to an input of the operational amplifier.

17. The system of claim 13 , wherein an increase in a number of the plurality of fans being in operation reduces the input resistance to the operational amplifier, and the reduction of the input resistance to the operational amplifier increases a gain of the operational amplifier to cause an output voltage of the operational amplifier to be increased relative to the voltage reference.

18. The circuit of claim 3 , wherein the output of the operational amplifier is to drive each of the resistors of the plurality of fans.

19. The circuit of claim 18 , wherein the operational amplifier is to provide a flow of current to the resistors of the plurality of fans over a signal path connected to the resistors of the plurality of fans, and wherein the signal path is further connected to the input of the operational amplifier.

20. The circuit of claim 4 , wherein the change in input resistance corresponds to a change in a number of the plurality of fans that are in operation.

21. The method of claim 6 , wherein driving the fault resistors of the plurality of fans comprises driving a flow of current to the fault resistors of the plurality of fans over a signal path, the signal path connected to the input of the operational amplifier.

Assignees

• Hewlett Packard Development Co

Inventors

• Teixido Rovira Pedro Miguel
• Sanz Ananos Santiago
• Bayona Alcolea Fernando

Classifications

• G01R31/69

  of terminals at the end of a cable or a wire harness; of plugs; of sockets, e.g. wall sockets or power sockets in appliances · CPC title

• G01R17/00

  Measuring arrangements involving comparison with a reference value, e.g. bridge · CPC title

• F04D29/582

  specially adapted for elastic fluid pumps · CPC title

• F04D27/001 Primary

  Testing thereof; Determination or simulation of flow characteristics; Stall or surge detection, e.g. condition monitoring · CPC title

• G01R31/045

  Physics · mapped topic