HW and Methods for Improving Safety Protocol in Wireless Chargers

Patent metadata

Field	Value
Publication number	US-2020366121-A1
Application number	US-201916413283-A
Country	US
Kind code	A1
Filing date	May 15, 2019
Priority date	May 15, 2019
Publication date	Nov 19, 2020
Grant date	—

Abstract

An over-voltage protection circuit and methods of operation are provided. In one embodiment, a method includes monitoring a voltage at an output of a rectifier, a voltage at an output of a voltage regulator, or a combination thereof. The method further includes determining the over-voltage condition based on the monitoring; and in response to determining the over-voltage condition, regulating the voltage at the output of the rectifier in accordance with a voltage difference between the voltage at the output of the rectifier and the voltage at the output of the voltage regulator.

First claim

What is claimed is:

1 . An over-voltage protection circuit comprising:
a first differential amplifier, a first input of the first differential amplifier coupled to an output of a rectifier, a second input of the first differential amplifier coupled to an output of a voltage regulator; a second differential amplifier, a first input of the second differential amplifier coupled to an output of the first differential amplifier, a second input of the second differential amplifier coupled to a first reference voltage; a comparator, a first input of the comparator coupled to the output of the first differential amplifier, a second input of the comparator coupled to a second reference voltage; a switch, an input of the switch coupled to the output of the second differential amplifier, a control terminal of the switch coupled to an output of the comparator; and a regulating circuit, an input of the regulating circuit coupled to the output of the rectifier, a control terminal of the regulating circuit coupled to the output of the switch, an output of the regulating circuit coupled to reference ground.

2 . The over-voltage protection circuit of claim 1 , wherein the first differential amplifier is configured to provide an output voltage corresponding to an amplified difference between a voltage at the output of the rectifier and a voltage at the output of the voltage regulator, the output voltage of the first differential amplifier provided to each of the comparator and the second differential amplifier.

3 . The over-voltage protection circuit of claim 1 , wherein the second differential amplifier is configured to provide a control voltage to the control terminal of the regulating circuit, a value of the control voltage corresponding to an amplified voltage difference between a voltage at the output of the rectifier and a voltage at the output of the voltage regulator in reference to the first reference voltage.

4 . The over-voltage protection circuit of claim 1 , wherein the comparator is configured to provide a control signal to the switch, a value of the control signal corresponding to an amplified voltage difference between a voltage at the output of the rectifier and a voltage at the output of the voltage regulator in reference to the second reference voltage.

5 . The over-voltage protection circuit of claim 1 , wherein the switch is activated in response to an amplified voltage difference between a voltage at the output of the rectifier and a voltage at the output of the voltage regulator exceeding a first threshold, the voltage at the output of the rectifier exceeding a second threshold, the voltage the output of the voltage regulator exceeding a third threshold, or a combination thereof.

6 . The over-voltage protection circuit of claim 1 , wherein the regulating circuit is configured to regulate a voltage at the output of the rectifier in accordance with a control voltage provided by the second differential amplifier.

7 . The over-voltage protection circuit of claim 1 , wherein the regulating circuit comprises an active device and a dissipating element.

8 . A device comprising:
a rectifier configured to receive an alternating current (AC) voltage and output a direct current (DC) voltage; a voltage regulator configured to receive the DC voltage and output a regulated DC voltage; a monitoring circuit comprising a first differential amplifier, a second differential amplifier, a comparator, and a switch, the monitoring circuit configured to monitor the DC voltage, the regulated DC voltage, a difference between the DC voltage and the regulated DC voltage, or a combination thereof; and a regulating circuit configured to regulate the DC voltage in response to the monitoring circuit determining that the AC voltage exceeds a steady-state operating condition.

9 . The device of claim 8 , wherein the monitoring circuit further comprises a multiplexer, a second comparator, and a third comparator, wherein the regulating circuit is activated based on a combinational logic of a value of the DC voltage, the regulated DC voltage, and a voltage difference between the DC voltage and the regulated DC voltage.

10 . The device of claim 8 , further comprising a microcontroller configured to communicate an End Power Transfer (EPT) request to stop the AC voltage in response to the AC voltage exceeding the steady-state operating condition.

11 . The device of claim 10 , wherein the microcontroller is configured to communicate the EPT request after a delay period is elapsed from a time that the regulating circuit begins to regulate the DC voltage.

12 . The device of claim 10 , wherein communicating the EPT request is communicated using an in-band communication path.

13 . The device of claim 8 , wherein the regulating circuit is further configured to stop regulating the DC voltage after an elapsing of a programmable time period at which time the rectifier is configured in a hard over-voltage protection mode to stop receiving the AC voltage.

14 . The device of claim 8 , further comprising a load configured to receive the regulated DC voltage.

15 . A method for regulating an over-voltage condition in a wireless power system, the method comprising:
monitoring a voltage at an output of a rectifier, a voltage at an output of a voltage regulator, or a combination thereof; determining the over-voltage condition based on the monitoring; and in response to determining the over-voltage condition, regulating the voltage at the output of the rectifier in accordance with a voltage difference between the voltage at the output of the rectifier and the voltage at the output of the voltage regulator.

16 . The method of claim 15 , further comprising communicating an End Power Transfer (EPT) request using an in-band communication path after determining the over-voltage condition.

17 . The method of claim 16 , wherein communicating the EPT request is delayed for a set length of time after determining the over-voltage condition.

18 . The method of claim 15 , wherein monitoring the voltages comprises continuously comparing one or more of the voltage at the output of the rectifier, the voltage at the output of the voltage regulator, or a voltage difference between the voltage at the output of the rectifier and the voltage at the output of the voltage regulator to a respective reference voltage.

19 . The method of claim 18 , wherein each respective reference voltage is a programmable value.

20 . The method of claim 18 , wherein determining the over-voltage condition based on the monitoring comprises determining that one or more combinational logic of the output of the comparing satisfies the over-voltage condition.

Assignees

• St Microelectronics Asia Pacific Pte Ltd

Inventors

• Guedon Yannick

Classifications

• H02J7/60

  including safety or protection arrangements · CPC title

• H02J50/10 Primary

  using inductive coupling · CPC title

• H02J50/80

  involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices · CPC title

• H02J50/12

  of the resonant type · CPC title

• H02J7/025

  Electricity · mapped topic