Foreign object detection method and power system capable of detecting foreign object

Patent metadata

Field	Value
Publication number	US-10705497-B2
Application number	US-201815996516-A
Country	US
Kind code	B2
Filing date	Jun 3, 2018
Priority date	Jun 21, 2017
Publication date	Jul 7, 2020
Grant date	Jul 7, 2020

Abstract

A power system capable of detecting a foreign object, includes a power supplier side, a power receiver side, and a cable. The power supplier side includes a power converter, a foreign object detection and control circuit, and a pull-up circuit. The power converter supplies a supply voltage to the power receiver side according to a power supply control signal. The foreign object detection and control circuit generates the power supply control signal for controlling the power converter, and generates a foreign object detection and control signal according to a voltage at a supplier transmission node of the power supplier side, for determining whether a foreign object exists in the power receiver side. The pull-up circuit adjusts a level of a supply current which is supplied from the supplier transmission node to the power receiver side.

First claim

What is claimed is:

1. A foreign object detection method for detecting whether a foreign object exists in a power receiver side in a power delivery loop formed by a power supplier side and the power receiver side, wherein the power supplier side and the power receiver side are configured to be coupled with each other through a cable which includes a positive power transmission line, a negative power transmission line, and a signal transmission line, the power supplier side having a supplier transmission node and the power receiver side having a receiver transmission node, and the signal transmission line transmitting a communication signal between the supplier transmission node and the receiver transmission node, the method comprising:
(A) providing a low current to the supplier transmission node, and determining whether a voltage at the supplier transmission node is higher than or equal to a first voltage;
(B1) when the step (A) determines that the voltage at the supplier transmission node is higher than or equal to the first voltage, indicating that the power supplier side and the power receiver side are not properly coupled with each other, then, the next step being (B2);
(B2) supplying the low current from the supplier transmission node to the power receiver side;
(C) when the step (A) determines that the voltage at the supplier transmission node is not higher than and not equal to the first voltage, determining that the power supplier side and the power receiver side are coupled with each other, then, supplying a high current from the supplier transmission node to the power receiver side, wherein the high current is higher than the low current;
(D) when the power supplier side and the power receiver side are determined coupled with each other and the high current is supplied from the supplier transmission node to the power receiver side, determining whether the voltage at the supplier transmission node is between a second voltage and a third voltage;
(E) when the step (D) determines that the voltage at the supplier transmission node is between the second voltage and the third voltage, which confirms that the power supplier side and the power receiver side are properly coupled with each other, keeping supplying the high current from the supplier transmission node to the power receiver side;
(F1) when the step (D) determines that the voltage at the supplier transmission node is not between the second voltage and the third voltage, indicating that a foreign object exists, then, the next step being (F2); and
(F2) stopping supplying the high current and changing to supplying the low current from the supplier transmission node to the power receiver side, to avoid damaging or rusting the receiver side.

2. The foreign object detection method of claim 1 , wherein the low current is a constant current, and wherein a level of the constant current is lower than a level of the high current.

3. The foreign object detection method of claim 1 , wherein the low current is a pulsating current, and wherein an average level of the pulsating current is lower than a level of the high current.

4. The foreign object detection method of claim 1 , further comprising: after a foreign object is determined to exist in step (F1) and the low current is supplied from the supplier transmission node to the power receiver side in step (F2),
(G) determining for another time whether the voltage at the supplier transmission node is higher than or equal to the first voltage.

5. The foreign object detection method of claim 4 , wherein when the step (G) determines that the voltage at the supplier transmission node is higher than or equal to the first voltage, indicating that the power supplier side and the power receiver side are not properly coupled with each other, then, the next step being (B2).

6. The foreign object detection method of claim 4 , wherein when the step (G) determines that the voltage at the supplier transmission node is not higher than and not equal to the first voltage, indicating that a foreign object exists, then, the next step being (F2).

7. The foreign object detection method of claim 1 , further comprising: when the step (E) confirms that the power supplier side and the power receiver side are properly coupled with each other, and the high current is supplied from the supplier transmission node to the power receiver side,
(H) determining whether power delivery communication between the power supplier side and the power receiver side fails.

8. The foreign object detection method of claim 7 , wherein when the step (H) determines that the power delivery communication between the power supplier side and the power receiver side fails, indicating that a foreign object exists, then, the next step being (F2).

9. A power system capable of detecting a foreign object, comprising:
a power supplier side, which is configured to be coupled to a power receiver side through a cable which includes a positive power transmission line, a negative power transmission line, and a signal transmission line the power system being adapted to detecting whether a foreign object exists in the power receiver side, the power supplier side having a supplier transmission node and the power receiver side having a receiver transmission node, and the signal transmission line transmitting a communication signal between the supplier transmission node and the receiver transmission node the power supplier side including:
a power converter configured to supply a supply voltage to the power receiver side according to a power supply control signal;

a foreign object detection and control circuit configured to generate the power supply control signal for controlling the power converter, and the foreign object detection and control circuit being further configured to generate a foreign object detection and control signal according to a voltage at the supplier transmission node, for determining whether a foreign object exists in the power receiver side; and
a pull-up circuit configured to adaptively adjust a level of a supply current which is supplied from the supplier transmission node to the power receiver side

wherein the foreign object detection and control circuit generates the foreign object detection and control signal according to the voltage at the supplier transmission node by the following steps:
(A) providing a low current to the supplier transmission node, and determining whether a voltage at the supplier transmission node is higher than or equal to a first voltage by the transmission voltage detection circuit, wherein the low current corresponds to a low level of the supply current;
(B1) when the step (A) determines that the voltage at the supplier transmission node is higher than or equal to the first voltage, indicating that the power supplier side and the power receiver side are not properly coupled with each other, then, the next step being (B2);
(B2) supplying the low current from the supplier transmission node to the power receiver side by the pull-up circuit;
(C) when the step (A) determines that the voltage at the supplier transmission node is not higher than and not equal to the first voltage, determining that the power supplier side and the power receiver side are coupled with each other, then, supplying a high current from the supplier transmission node to the power receiver side, wherein the high current corresponds to a high level of the supply current, wherein the high current is higher than the low current;
(D) when the power supplier side and the power receiver side are determined coupled with each other and the pull-up circuit supplies the high current from the supplier transmission node to the power receiver side, determining whether the voltage at the sup

Assignees

• Richtek Technology Corp

Inventors

• Chang Wei-Hsu
• Kim Jung-Won

Classifications

• G01V3/02 Primary

  operating with propagation of electric current · CPC title

• G05B1/02

  for comparing analogue signals (circuits for comparing the phase or frequency of two mutually-independent oscillations H03D13/00) · CPC title

• G01R31/40

  Testing power supplies (testing photovoltaic devices H02S50/10) · CPC title

• G05B2219/2639

  Energy management, use maximum of cheap power, keep peak load low · CPC title

• G01R31/085

  in power transmission or distribution lines, e.g. overhead · CPC title