Induction heating circuit, protection circuit and cooling system for an appliance

Patent metadata

Field	Value
Publication number	US-12144087-B2
Application number	US-201917256977-A
Country	US
Kind code	B2
Filing date	Jun 28, 2019
Priority date	Jun 29, 2018
Publication date	Nov 12, 2024
Grant date	Nov 12, 2024

Abstract

An induction heating circuit for an appliance, the induction heating circuit comprising: an AC power supply with an AC monitoring output connected to the active line of the AC power supply, the AC monitoring output providing an indication of current being drawn from the AC power supply; a control circuit comprising at least one processor and a semiconductor current sensor, the semiconductor current sensor arranged to i) detect the current being drawn from the AC power supply and ii) output an output voltage based on the detected current; and an induction driving circuit for driving an inductor of the appliance comprising a semiconductor switch, wherein the semiconductor switch is controlled by the processor based on, at least, the output voltage.

First claim

The invention claimed is:

1. A protection circuit for protecting an induction heating circuit in an appliance, the protection circuit comprising:
a monitoring circuitry arranged to monitor a switching device in an induction heating circuit, wherein a first voltage, a second voltage and a current are monitored by the protection circuit; and
logic circuitry configured for clamping a switching signal for the switching device on the basis of the first voltage, second voltage, and current, wherein the first voltage is indicative of a turn on voltage across the switching device, the second voltage is indicative of a maximum over voltage across the switching device, and the current is indicative of a maximum current through the switching device.

2. The protection circuit of claim 1 wherein the monitoring circuitry comprises high speed comparators to compare the first voltage, second voltage and current against respective predefined thresholds.

3. The protection circuit of claim 1 wherein the protection circuit comprises optocouplers arranged to provide electrical isolation and transfer values associated with the first voltage, the second voltage and the current to the logic circuitry.

4. The protection circuit of claim 1 further comprising at least one monostable multivibrator arranged to stretch a first voltage associated with the first voltage, a second voltage signal associated with the second voltage and a current signal associated with the current.

Assignees

• Breville R & D Pty Ltd

Inventors

• Thie Johnson
• Hellmers Duncan
• Mcclean Stephen John

Classifications

• H05K7/20136

  Forced ventilation, e.g. by fans (H05K7/202 takes precedence) · CPC title

• H05B6/102

  the metal pieces being rotated while induction heated · CPC title

• H05B6/06 Primary

  Control, e.g. of temperature, of power · CPC title

• H03K5/24

  the characteristic being amplitude · CPC title

• G01R19/0092

  Measuring current only · CPC title