US Patent 11348417 Smart doorbell system and chime circuit

A smart doorbell system includes a doorbell switch, an input device, a chime circuit, and a ring circuit. A chime circuit includes a power connection terminal and a first rectifier circuit and a second rectifier circuit coupled to the power connection terminal and connected in parallel. The power connection terminal receives an alternating current including a first direction current and a second direction current that alternate. The input device is coupled to the chime circuit and generates a control signal. The control signal controls one of the first and second direction currents to pass through a corresponding one of the first and second rectifier circuits. The doorbell switch is coupled to the chime circuit and the ring circuit. A trigger signal is generated through the other one of the first and second direction currents when the doorbell switch is pressed, such that the ring circuit produces a ringing sound.