POWER STEALING CIRCUITRY FOR A CONTROL DEVICE

• US 20120155137A1
• Filed: 12/14/2011
• Published: 06/21/2012
• Est. Priority Date: 07/29/2008
• Status: Active Grant

• Current Assignee: Ademco Inc. (Resideo Technologies, Inc.)
• Original Assignee: Honeywell International Inc.
• Inventors: Simard, Pierre, Meilleur, Benoit, Tousignant, Daniel
• Granted Patent: US 9,071,145 B2
• Time in Patent Office: Days
• US Class Current: 363/126
• CPC Class Codes: H02J 9/06 with automatic change-over , e.g. UPS systems
• CPC Class Codes: H02M 1/0006 Arrangements for supplying an adequate voltage to the control circuit of converters
• CPC Class Codes: H02M 5/2573 with control circuit
• CPC Class Codes: H02M 7/04 by static converters
• CPC Class Codes: H02M 7/2176 comprising a passive stage to generate a rectified sinusoidal voltage and a controlled switching element in series between such stage and the output

Abstract

A power stealing circuit for stealing power to operate a control device is disclosed. In one illustrative embodiment, power may be periodically or intermittently diverted from a power source to a power stealing block. When power is diverted to the power stealing block, the power stealing block may steal power from the power source and store the stolen power on a storage device. The storage device may then provide operating power to a control device. In some embodiments, the power stealing block may include a first path for charging the storage device when a switch is ON, and a second path for charging the storage device when the switch is off.

Claims

1. (canceled)

2. A power stealing block for stealing power from an AC power source, the stolen power being used, at least at times, to power a control device, wherein the control device is configured to switch power “

on” and

“

off”

from the AC power source to a building control device, the power stealing block comprising;

an input for receiving an AC signal;

an output;

a rectifier for rectifying the AC signal, resulting in a rectified AC signal;

a switch; and

a controller, the controller allowing power to be stolen from the AC power source to the output of the power stealing block through the switch when the rectified AC signal is below a first voltage, and not allowing power to be stolen from the AC power source to the output of the power stealing block through the switch when the rectified AC signal is above a second voltage.

3. The power stealing block of claim 2, wherein the first voltage and the second voltage are the same.

4. The power stealing block of claim 2, wherein the controller switches the switch to an “

on”

state to when stealing power.

5. The power stealing block of claim 4, wherein when the switch is in the “

on”

state, the power stealing block diverts stolen power from the AC power source to a charge storage device.

6. The power stealing block of claim 5, wherein the charge storage device includes a capacitor.

7. The power stealing block of claim 5, wherein the charge storage device includes a rechargeable battery.

8. The power stealing block of claim 5, wherein when the switch is in the “

on”

state, the output of the power stealing block diverts stolen power from the AC power source to power a control device that switches power “

on” and

“

off”

from the AC power source to a load.

9. The power stealing block of claim 2, wherein the building control device includes an AC unit.

10. The power stealing block of claim 2, wherein the building control device includes a heating unit.

11. The power stealing block of claim 2, wherein the building control device includes a motor.

12. The power stealing block of claim 2, further comprising a discriminator that is configured to determine when the rectified AC signal is above the second voltage.

13. The power stealing block of claim 2, further comprising a bypass resistance connected in parallel with the switch.

14. A power stealing block for stealing power from an AC power source, the stolen power being used, at least at times, to power a control device, wherein the control device switches power “

on” and

“

off”

from the AC power source to a load, the power stealing block comprising;

a charge storage device for storing a charge, wherein the charge storage device powers the control device at times;

an input for receiving an AC signal;

a rectifier for rectifying the AC signal, resulting in a rectified AC signal;

a switch having an “

on”

state and an “

off”

state, the switch passing the rectified AC signal either directly or indirectly to the charge storage device when the switch is in the “

on”

state, and the switch not passing the rectified AC power to the charge storage device when the switch is in the “

off”

state; and

a controller for controlling the state of the switch, wherein the controller is configured to keep the switch in the “

off”

state when the rectified AC signal is above a first voltage.

15. The power stealing block of claim 14, wherein the controller switches the switch to the “

on”

state when the rectified AC signal drops below the first voltage.

16. The power stealing block of claim 14, wherein the charge storage device includes a capacitor.

17. The power stealing block of claim 14, wherein the charge storage device includes a rechargeable battery.

18. The power stealing block of claim 15, wherein the controller is configured to keep the switch in the “

off”

state when the voltage across the charge storage device is above a second voltage.

19. The power stealing block of claim 18, wherein the first voltage is the same as the second voltage.

20. A method for stealing power from an AC power source, wherein the stolen power is used, at least at times, to power a control device, wherein the control device switches power “

on” and

“

off”

from the AC power source to a load, the method comprising;

generating a rectified AC signal from the AC power source;

not allowing power to be stolen from the AC power source through a switch when the rectified AC signal is above a first voltage; and

allowing power to be stolen from the AC power source through the switch when the rectified AC signal is below a second voltage.

21. The method of claim 20, wherein the first voltage and the second voltage are the same.

22. A method for stealing power from an AC power source, wherein the stolen power is used, at least at times, to power a control device, wherein the control device switches power “

on” and

“

off”

from the AC power source to a load, the AC power source providing an AC voltage signal having an amplitude, the method comprising;

diverting power from the AC power source to a power stealing block during each of a sequence of power stealing pulses, wherein each of the power stealing pulses have a pulse width that is at least partially dependent upon the amplitude of the AC voltage signal; and

when power is diverted to the power stealing block during each of the power stealing pulses, charging a charge storage device; and

providing operating power to the control device from the charge storage device.

23. A method for stealing power from an AC power source, the stolen power being used, at least at times, to power a control device, wherein the control device is configured to switch power “

on” and

“

off”

from the AC power source to a building control device, the method comprising;

periodically or intermittently diverting power from the AC power source to a power stealing block;

when power is diverted to the power stealing block, charging a charge storage device via a first path if it is desirable to charge the charge storage device faster, and charging the charge storage device via a second path if it is desirable to charge the charge storage device slower; and

providing operating power to the control device from the charge storage device.

24. The method of claim 23 wherein the charge storage device is charged via the second path if a voltage of the diverted power is above a threshold value.

25. The method of claim 23 wherein the charge storage device is charged via the second path if a voltage across the charge storage device is above a threshold value.