Abstract: 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.

Abstract: 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.

Abstract: A power apparatus for an external load comprises a transformer, a power coordinating unit, a control unit and an internal load. The transformer is adapted for transforming an input voltage into an output voltage and an auxiliary voltage in response to an operating signal. The transformer comprises a first coil, a second coil and an auxiliary coil electromagnetically coupled to one another. The power coordinating unit comprises a first resistor, a transistor, a second resistor, a diode and a capacitor. The control unit is coupled between the first node and the first coil and configured to selectively generate the operating signal. When the control unit operates in a protective mode, the control unit is configured not to generate the operating signal, the power coordinating unit is configured to generate a coordinating current supplied to the internal load by using a starting voltage of the first node.

Abstract: A power apparatus for an external load comprises a transformer, a power coordinating unit, a control unit and an internal load. The transformer is adapted for transforming an input voltage into an output voltage and an auxiliary voltage in response to an operating signal. The transformer comprises a first coil, a second coil and an auxiliary coil electromagnetically coupled to one another. The power coordinating unit comprises a first resistor, a transistor, a second resistor, a diode and a capacitor. The control unit is coupled between the first node and the first coil and configured to selectively generate the operating signal. When the control unit operates in a protective mode, the control unit is configured not to generate the operating signal, the power coordinating unit is configured to generate a coordinating current supplied to the internal load by using a starting voltage of the first node.

Abstract: A power device includes a power supply module, a first electrical isolation unit, a second electrical isolation unit, a feedback control unit, and a comparing unit. The power supply module includes a feedback compensating terminal and an output terminal, the feedback compensating terminal provides a related voltage of output power, and the output terminal provides an output voltage. When the related voltage of output power is smaller than the predetermined voltage, the comparing unit controls the first electrical isolation unit to change operation of the feedback control unit and the second electrical isolation unit, to allow the power supply module to adjust the output voltage.

Abstract: An inverter circuit (20) includes a transformer (T2) including a primary winding and a secondary winding including a high voltage terminal, a first copper foil (P21), a power stage circuit (21) electrically connected to the primary winding, a detection circuit (22) including a second copper foil (P22) and an impedance (Z2), a protection circuit (23) outputting a protection signal, and a pulse width modulation controller (24) controlling output of the power stage circuit according to the protection signal. The second copper foil and the first copper foil are separated. An equivalent capacitor is formed between the second copper foil and the first copper foil, detecting voltage output from the high voltage terminal. The impedance is electrically connected between the second copper foil and ground, dividing a voltage detected by the equivalent capacitor.

Abstract: A power device includes a power supply module, a first electrical isolation unit, a second electrical isolation unit, a feedback control unit, and a comparing unit. The power supply module includes a feedback compensating terminal and an output terminal, the feedback compensating terminal provides a related voltage of output power, and the output terminal provides an output voltage. When the related voltage of output power is smaller than the predetermined voltage, the comparing unit controls the first electrical isolation unit to change operation of the feedback control unit and the second electrical isolation unit, to allow the power supply module to adjust the output voltage.

Abstract: An inverter circuit (20) includes a transformer (T2) including a primary winding and a secondary winding including a high voltage terminal, a first copper foil (P21), a power stage circuit (21) electrically connected to the primary winding, a detection circuit (22) including a second copper foil (P22) and an impedance (Z2), a protection circuit (23) outputting a protection signal, and a pulse width modulation controller (24) controlling output of the power stage circuit according to the protection signal. The second copper foil and the first copper foil are separated. An equivalent capacitor is formed between the second copper foil and the first copper foil, detecting voltage output from the high voltage terminal. The impedance is electrically connected between the second copper foil and ground, dividing a voltage detected by the equivalent capacitor.