US Patent 10325453 Doorbell device and associated control method

A doorbell device has a first power input terminal and a second power input terminal. The doorbell device is coupled to a chime device. The doorbell device includes a current sensing circuit, a switch circuit, and a processing circuit. The current sensing circuit is coupled to the first power input terminal, and generates a sensing voltage according to a current flowing through the current sensing circuit. The switch circuit is coupled between the current sensing circuit and the second power input terminal. The switch circuit changes the conducting state in response to a control signal. The processing circuit is configured to provide the control signal and determine the type of the chime device according to the sensing voltage.