Foreign matter detection circuit, wireless charging system and foreign matter detection method

Abstract

The invention belongs to the technical field of wireless charging, and discloses a foreign matter detection circuit, a wireless charging system and a foreign matter detection method. The foreign matter detection circuit comprises an inverter switch module, a coil switching module and a control module; the control module sends a coil detection signal to the coil switching module when the wireless charging system is in a standby state, so that the coil switching module is connected with the wireless transmitting coil, outputs a closing signal to the inverter switch module when the wireless transmitting coil is connected, and when the inverter switch is closed, the input voltage of the inverter switch module and the coil voltage of the wireless transmitting coil are acquired to determine a quality factor value, and whether foreign matters exist in the electromagnetic wave transmission range of the wireless charging system or not is judged according to the quality factor value. Compared with the prior art that two independent circuits are generally used for detecting current and voltage respectively, the foreign matter detection circuit can be used for object detection, Q value detection and coil selection at the same time, and the standby awakening time, the standby loss and the circuit cost are reduced.

Description

technical field [0001] The invention relates to the technical field of wireless charging, in particular to a foreign object detection circuit, a wireless charging system and a foreign object detection method. Background technique [0002] At present, in order to reduce standby power and prevent metal foreign objects from being heated in wireless charging systems, intermittent object detection and Q value detection functions are usually added during the standby phase. However, at present, the two functions usually use two independent circuits to detect the two variables of current and voltage respectively, which have the problems of long time consumption, long system wake-up time and high cost. [0003] The above content is only used to assist in understanding the technical solution of the present invention, and does not mean that the above content is admitted as prior art. Contents of the invention [0004] The main purpose of the present invention is to provide a foreign...

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Problems solved by technology

[0004] The main purpose of the present invention is to provide a foreign object detection circuit, a wireless charging system and a foreign object detection method, aiming to solve the technical problems of long time-consuming Q value detection in the existing wireless charging process, long system wake-up time and high cost

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