Thermostat with self-configuring connections to facilitate do-it-yourself installation

Patent metadata

Field	Value
Publication number	US-2018181148-A1
Application number	US-201815897757-A
Country	US
Kind code	A1
Filing date	Feb 15, 2018
Priority date	Feb 24, 2011
Publication date	Jun 28, 2018
Grant date	—

Abstract

A circuit includes a monitoring circuit that monitors a voltage and a switching circuit. Closing the switching circuit causes an external AC load to receive power from an external AC source. The circuit further includes a control circuit that opens the switching circuit for a time interval, where the time interval begins after the voltage is below a lower threshold. The control circuit also ends the time interval after the voltage exceeds an upper threshold, where the time interval is short enough that the operation of the AC load is not affected during the time interval. The circuit also includes a power harvesting circuit that harvests power from the external AC source to raise the voltage during the time interval.

First claim

What is claimed is:

1 . A method comprising:
closing a switching circuit for powering an external AC load, wherein closing the switching circuit causes the external AC load to receive power from an external AC source; monitoring a voltage; opening the switching circuit for a time interval, wherein the time interval begins after the voltage is below a lower threshold; harvesting power from the external AC source to raise the voltage during the time interval; and ending the time interval after the voltage exceeds an upper threshold, wherein the time interval is short enough that the operation of the AC load is not affected during the time interval.

2 . The method of claim 1 , wherein the voltage is associated with a capacitive element that is charged by the power harvested from the AC source.

3 . The method of claim 1 , further comprising:
opening the switching circuit for powering the external AC load, wherein opening the switching circuit causes the external AC load to stop receiving power from an external AC source and stopping a function associated with the AC load; and harvesting power from the external AC source to raise the voltage while the AC load is unpowered.

4 . The method of claim 1 , wherein the power harvested from the external AC source passes through a diode rectifier bridge before raising the voltage.

5 . The method of claim 1 , further comprising:
receiving control signals from a microcontroller to control the switching circuit, wherein the control signals pass through an isolation barrier between the microcontroller and the switching circuit.

6 . The method of claim 1 , wherein the opening of the switching circuit occurs at a zero-crossing of the AC source.

7 . The method of claim 1 , wherein the switching circuit comprises a pair of back-to-back MOSFETs.

8 . The method of claim 1 , wherein the voltage provides power to the switching circuit.

9 . The method of claim 1 , further comprising detecting an electrical fault associated with an input to the switching circuit.

10 . The method of claim 1 , wherein the AC load is part of an HVAC triggering circuit.

11 . A circuit comprising:
a monitoring circuit that monitors a voltage; a switching circuit, wherein:
closing the switching circuit causes an external AC load to receive power from an external AC source;
a control circuit that:
opens the switching circuit for a time interval, wherein the time interval begins after the voltage is below a lower threshold; and
ends the time interval after the voltage exceeds an upper threshold, wherein the time interval is short enough that the operation of the AC load is not affected during the time interval; and
a power harvesting circuit that harvests power from the external AC source to raise the voltage during the time interval.

12 . The circuit of claim 11 , wherein:
the control circuit further opens the switching circuit for powering the external AC load, wherein opening the switching circuit causes the external AC load to stop receiving power from an external AC source and stopping a function associated with the AC load; and the power harvesting circuit further harvests power from the external AC source to raise the voltage while the AC load is unpowered.

13 . The circuit of claim 11 , further comprising a diode rectifier bridge, wherein the power harvested from the external AC source passes through a diode rectifier bridge before raising the voltage.

14 . The circuit of claim 11 , further comprising an isolation barrier, wherein the control circuit further receives control signals from a microcontroller to control the switching circuit, wherein the control signals pass through the isolation barrier between the microcontroller and the switching circuit.

15 . The circuit of claim 11 , wherein the opening of the switching circuit occurs at a zero-crossing of the AC source.

16 . A control device comprising:
a capacitive element; a monitoring circuit that monitors a voltage associated with the capacitive element; a switching circuit, wherein:
closing the switching circuit causes an external AC load to receive power from an external AC source;
a control circuit that:
opens the switching circuit for a time interval, wherein the time interval begins after the voltage is below a lower threshold; and
ends the time interval after the voltage exceeds an upper threshold, wherein the time interval is short enough that the operation of the AC load is not affected during the time interval; and
a power harvesting circuit that harvests power from the external AC source to charge the capacitive element during the time interval.

17 . The system of claim 16 , wherein the switching circuit comprises a pair of back-to-back MOSFETs.

18 . The system of claim 16 , wherein the voltage associated with the capacitive element provides power to the switching circuit.

19 . The system of claim 16 , wherein the control circuit further detects an electrical fault associated with an input to the switching circuit.

20 . The system of claim 16 , wherein the AC load is part of an HVAC triggering circuit.

Assignees

• Google Llc

Inventors

• Warren Daniel Adam
• Fiennes Hugo
• Dutra Jonathan Alan
• Bell David
• Fadell Anthony Michael
• Rogers Matthew Lee

Classifications

• F24F2120/14

  Activity of occupants · CPC title

• F24F11/61

  using timers · CPC title

• Y02T10/88

  Optimized components or subsystems, e.g. lighting, actively controlled glasses · CPC title

• Y10T29/49826

  Assembling or joining · CPC title

• F24F2110/10

  Temperature · CPC title