A control method of a switching circuit, a control circuit of the switching circuit, and the switching circuit are provided. The switching circuit includes an inductor or a transformer. An operational amplification is performed on an output feedback voltage and a first reference voltage of the switching circuit to obtain a compensation voltage. The compensation voltage controls an on-time of a main switch of the switching circuit. When the current of the inductor or the transformer drops to a threshold, after a time, the main switch is switched from off to on, and the output feedback voltage controls the time. When the output feedback voltage is higher than a first threshold voltage, the compensation voltage is pulled down. When the output feedback voltage is lower than a second threshold voltage, the compensation voltage is pulled up.

A control method of a switching circuit, a control circuit of the switching circuit, and the switching circuit are provided. The switching circuit includes an inductor or a transformer. An operational amplification is performed on an output feedback voltage and a first reference voltage of the switching circuit to obtain a compensation voltage. The compensation voltage controls an on-time of a main switch of the switching circuit. When the current of the inductor or the transformer drops to a threshold, after a time, the main switch is switched from off to on, and the output feedback voltage controls the time. When the output feedback voltage is higher than a first threshold voltage, the compensation voltage is pulled down. When the output feedback voltage is lower than a second threshold voltage, the compensation voltage is pulled up.

A power converter can include a magnetic energy storage element, a main switch, a synchronous rectifier switch, and an energy recovery circuit. The energy recovery circuit can include a resonant circuit and an auxiliary switch configured to operate in conjunction with the main and synchronous rectifier switches to store energy in the resonant circuit and deliver energy therefrom to reduce switching losses associated with the main and synchronous rectifier switches. The converter can be a buck, boost, buck-boost, or other converter type. The auxiliary switch may be operated according to a two-pulse control mode or using a conventional buck converter controller with additional delay elements. The resonant circuit inductance may be a discrete inductor or a parasitic inductance, such as a PCB trace, which may be designed to provide a desired inductance value selected to efficiently provide sufficient energy to achieve reduced switching losses of the main and auxiliary switches.

A power converter can include a magnetic energy storage element, a main switch, a synchronous rectifier switch, and an energy recovery circuit. The energy recovery circuit can include a resonant circuit and an auxiliary switch configured to operate in conjunction with the main and synchronous rectifier switches to store energy in the resonant circuit and deliver energy therefrom to reduce switching losses associated with the main and synchronous rectifier switches. The converter can be a buck, boost, buck-boost, or other converter type. The auxiliary switch may be operated according to a two-pulse control mode or using a conventional buck converter controller with additional delay elements. The resonant circuit inductance may be a discrete inductor or a parasitic inductance, such as a PCB trace, which may be designed to provide a desired inductance value selected to efficiently provide sufficient energy to achieve reduced switching losses of the main and auxiliary switches.

A device control method includes: receiving a turn-on signal of a target device, the turn-on signal being adapted to trigger the target device to start working; obtaining a compensation duration, the compensation duration being adapted to offset a delay caused when a voltage zero-crossing detection component detects voltage zero-crossing; and when a zero-crossing signal is received, after the compensation duration, controlling a designated component in the target device to be turned on or off. The zero-crossing signal is a signal sent when the voltage zero-crossing detection component detects that a voltage passes through a zero point. A power supply voltage detection method and a power supply voltage detection apparatus are also disclosed.

A device control method includes: receiving a turn-on signal of a target device, the turn-on signal being adapted to trigger the target device to start working; obtaining a compensation duration, the compensation duration being adapted to offset a delay caused when a voltage zero-crossing detection component detects voltage zero-crossing; and when a zero-crossing signal is received, after the compensation duration, controlling a designated component in the target device to be turned on or off. The zero-crossing signal is a signal sent when the voltage zero-crossing detection component detects that a voltage passes through a zero point. A power supply voltage detection method and a power supply voltage detection apparatus are also disclosed.

A ripple voltage detector circuit comprises a pulse generator, a direct current-to-direct current (DC-DC) converter coupled to the pulse generator, and a first control loop coupled to the pulse generator and the DC-DC converter. The first control loop is configured to measure an output voltage of the DC-DC converter, determine an output ripple voltage of the output voltage, determine a ripple coefficient based on the output ripple voltage, determine a reference peak inductor current based on the ripple coefficient, and determine a peak value of an inductor current during a switching cycle, and transition a switching state of the DC-DC converter based on the reference peak inductor current and the peak value of the inductor current.

A ripple voltage detector circuit comprises a pulse generator, a direct current-to-direct current (DC-DC) converter coupled to the pulse generator, and a first control loop coupled to the pulse generator and the DC-DC converter. The first control loop is configured to measure an output voltage of the DC-DC converter, determine an output ripple voltage of the output voltage, determine a ripple coefficient based on the output ripple voltage, determine a reference peak inductor current based on the ripple coefficient, and determine a peak value of an inductor current during a switching cycle, and transition a switching state of the DC-DC converter based on the reference peak inductor current and the peak value of the inductor current.

The present disclosure provides a control circuit to power a load, the circuit generally comprising a first switch such as a TRIAC to switch on and off and power the load based upon user demand. The circuit is also comprised of a second connected in parallel with the TRIAC, the second switch switching to a conducting state at a zero-crossing of the source before becoming completely saturated. Once the second switch is saturated, the first switch switches from a non-conducting state to a conducting state, which minimizes conducted EMI generated in the circuit.

The present disclosure provides a control circuit to power a load, the circuit generally comprising a first switch such as a TRIAC to switch on and off and power the load based upon user demand. The circuit is also comprised of a second connected in parallel with the TRIAC, the second switch switching to a conducting state at a zero-crossing of the source before becoming completely saturated. Once the second switch is saturated, the first switch switches from a non-conducting state to a conducting state, which minimizes conducted EMI generated in the circuit.