Power stealing circuitry for a control device

• US 9,071,145 B2
• Filed: 12/14/2011
• Issued: 06/30/2015
• 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
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): Pham, Duc M
• Application Number:
  US13/325,389
• Publication Number:
  US 20120155137A1
• Time in Patent Office: 1,294 Days
• Field of Search: 307/102
• US Class Current: 1/1
• 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. 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 by supplying a first non-zero current via a first path if it is desirable to charge the charge storage device faster, and charging the charge storage device by supplying a second non-zero current via a second path if it is desirable to charge the charge storage device slower, wherein the first non-zero current is different from the second non-zero current; and

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

2. The method of claim 1 wherein the charge storage device is charged via the second path if a voltage of the diverted power is above a threshold value.

3. The method of claim 1 wherein the charge storage device is charged via the second path if a voltage across the charge storage device is above a threshold value.