Method, apparatus and system for determining power supply to a load

• US 7,793,117 B2
• Filed: 10/12/2006
• Issued: 09/07/2010
• Est. Priority Date: 10/12/2006
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Smith, David E.
• Primary Examiner(s): Cao; Chun
• Application Number:
  US11/581,046
• Publication Number:
  US 20080103609A1
• Time in Patent Office: 1,426 Days
• Field of Search: 713/300, 713/320
• US Class Current: 713/300
• CPC Class Codes: B41J 2/04548 Details of power line section of control circuit
• CPC Class Codes: B41J 2/04586 controlling heads of a type not covered by groups B41J2/04575 - B41J2/04585, or of an undefined type

Abstract

Embodiments of determining power to be supplied to a load are disclosed. In one embodiment, the method includes determining an amount of power to supply to a load included in a first system having a plurality of loads, using a relationship between a change in the voltage provided by a power source to the first system caused due to a current drawn by one or more other systems coupled to the power source and a corresponding change in current supplied by the power source to the first system monitored over a predetermined time interval, to reduce a magnitude of the change in the voltage resulting from the power source, and causing the determined amount of the power to be supplied to the load.

Claims

1. A method comprising:

determining an amount of power to supply to a load included in a first system having a plurality of loads, using a relationship between a change in the voltage provided by a power source to the first system caused by current drawn during operation of one or more other systems coupled to the power source and a corresponding change in the current supplied by the power source to the first system monitored over a predetermined time interval, to reduce a magnitude of the change in the voltage resulting from the power source; and

causing the determined amount of the power to be supplied to the load.

2. The method as recited in claim 1, further comprising:

determining the relationship between the change in the voltage and the corresponding change in the current.

3. The method as recited in claim 2, wherein:

the determining the relationship includes measuring a plurality of voltages provided by the power source to the first system and measuring a plurality of currents provided by the power source to the first system corresponding to the plurality of the voltages.

4. The method as recited in claim 3, wherein:

the determining the relationship includes controlling the first system to dissipate a plurality of different amounts of the power in the load corresponding to the plurality of the voltages and the plurality of the currents.

5. The method as recited in claim 1, further comprising:

monitoring the voltage provided to the first system by the power source; and

detecting the change in the voltage provided by the power source caused from the operation of the one or more of the other systems coupled to the power source.

6. The method as recited in claim 1, wherein:

the using the relationship includes determining from the relationship an expected reduction in the magnitude of the change in the voltage to result from supplying the amount of the power to the load.

7. The method as recited in claim 2, wherein:

the determining the relationship includes determining an estimate of a magnitude of an impedance associated with the power source.

8. The method as recited in claim 2, wherein:

the determining the relationship includes determining a set of corresponding pairs of expected changes in the magnitude of the voltage resulting from changes in the current.

9. The method as recited in claim 2, wherein:

the determining the relationship includes determining a time interval during which the changes to the current provided by the power source to the one or more other systems coupled to the power source substantially equal zero.

10. The method as recited in claim 1, wherein:

the load includes a heater;

the first system includes a printing system; and

the power source includes an AC mains.

11. The method as recited in claim 1, wherein:

the determining the amount of power includes determining from the using the relationship the amount of the power sufficient to reduce the magnitude of the change in the voltage to a value at least as great as a lower operating voltage of a second load of the plurality of loads of first system coupled to the power source.

12. The method as recited in claim 1, wherein:

the determining the amount of power includes accessing a look-up table specifying the relationship using a desired amount of the reduction in the magnitude of the change in the voltage that results from the power source supplying the current corresponding to the amount of the power.

13. The method as recited in claim 12, wherein the desired amount of the reduction in the magnitude of the change in the voltage corresponds to a value of the voltage that exceeds a threshold voltage for proper operation of a second load coupled to the power source.

14. An apparatus, comprising:

a processing device configured to determine an amount of a power to be supplied to a load of a system having a plurality of loads, using a relationship between a change in the voltage provided by a power source to the system caused by current drawn during operation of one or more other systems coupled to the power source and a corresponding change in current supplied by the power source to the first system monitored over a predetermined time interval, to reduce a change in a value of a voltage resulting from the power source to the system.

15. The apparatus as recited in claim 14, further comprising:

a power controller configured to adjust the power supplied to the load according to the amount of the power determined.

16. The apparatus as recited in claim 14, wherein:

the processing device includes a configuration to determine the amount of the power so that the reduction in the change in the value of the voltage results in the value of the voltage provided by the power source exceeding a lower operating threshold voltage of a second load included in the system by at least a predetermined value.

17. The apparatus as recited in claim 14, further comprising:

a device configured to measure the value of the voltage and a value of a current provided to the system by the power source; and

wherein the processing device includes a configuration to determine a relationship between the change in the value of the voltage and a change in the value of the current provided to the system by the power source during a time interval in which the changes to current provided by the power source to the one or more other systems coupled to the power source substantially equal zero.

18. The apparatus as recited in claim 17, wherein:

the time interval corresponds to one or more of;

during power up of the system, periodically during operation of the system or, a predetermined time period during a day.

19. A system, comprising:

a device to determine an estimate of a voltage supplied by a power source to the system and an estimate of a current supplied by the power source to the system;

a heater;

a power converter to supply power to the heater; and

circuitry to determine an amount of the power to be supplied to the heater to reduce a change in the voltage caused by current drawn during operation of another system coupled to the power source monitored over a predetermined time interval.

20. The system as recited in claim 19, further comprising:

an image forming mechanism to form an image on media;

a DC power supply, wherein the circuitry includes a capability to determine the amount of the power, using a relationship between a change in the voltage supplied by the power source resulting from a change in the current supplied by the power source to the system, so that the voltage remains above an operating voltage threshold of the DC power supply during operation of the system.