Provided are a power supply conversion device and a charging control method. The device includes: a transformer; a first rectifier circuit connected to a primary winding of the transformer used for converting a received alternating current into a first direct current, a voltage value of the first direct current being a first direct-current voltage, and the transformer used for converting the first direct-current voltage into a second direct-current voltage; a voltage converter connected to a secondary winding of the transformer and used for converting the second direct-current voltage to output a constant direct-current voltage or a pulsating direct-current voltage; and a controller connected to the first rectifier circuit and the voltage converter and used for controlling the voltage converter to selectably output the constant direct-current voltage or the pulsating direct-current voltage according to a desired charging mode of a device to be charged connected to the power supply conversion device.

Provided are a power supply conversion circuit and a power supply conversion method. The power supply conversion circuit includes a first direct-current conversion circuit connected to an electric load, a secondary transformer coil connected to the first direct-current conversion circuit, and a primary transformer coil coupled to the secondary transformer coil. The primary transformer coil is configured to generate, based on an initial voltage inputted to the primary transformer coil, an electromagnetic field and couple the electromagnetic field to the secondary transformer coil. The secondary transformer coil is configured to generate an induced current by virtue of the electromagnetic field, generate a secondary output voltage based on the induced current, and transmit the secondary output voltage to the first direct-current conversion circuit. The first direct-current conversion circuit is configured to adjust, based on a predetermined demand voltage of the electric load, the secondary output voltage to obtain a target voltage.

A power supply conversion circuit and a charging device are provided. The power supply conversion circuit includes: a first voltage conversion circuit that converts a voltage when the voltage exceeds a preset voltage range and outputs the converted voltage; a post-stage voltage conversion circuit that receives the converted voltage and converts the converted voltage into a target voltage for outputting; and a signal feedback circuit that feeds back a signal to the first voltage conversion circuit according to the target voltage, so that the first voltage conversion circuit is synchronized with the post-stage voltage conversion circuit.

A power supply circuit includes a rectifier circuit, configured to convert an alternating current inputted to the rectifier circuit into a direct current; a primary power supply conversion circuit having an input end connected with an output end of the rectifier circuit, configured to convert an input voltage of the primary power supply conversion circuit which is out of a preset voltage range into an output voltage of the primary power supply conversion circuit within the preset voltage range; and a secondary power supply conversion circuit having an input end connected with an output end of the primary power supply conversion circuit, configured to convert a direct current voltage outputted by the primary power supply conversion circuit into a target direct current voltage. A lower limit of the preset voltage range is greater than a minimum working voltage of the secondary power supply conversion circuit.

Provided by the present disclosure are a power supply circuit and a charging device. The power supply circuit comprises a pulse transformer circuit and a first power supply conversion circuit. The pulse transformer circuit comprises a pulse transformer and a switch control circuit; a primary winding of the pulse transformer is connected to a power supply and is connected to the switch control circuit, and the switch control circuit is used to modulate the voltage on the primary winding into a pulse voltage; and the input terminal of the first power supply conversion circuit is connected to a secondary winding of the pulse transformer, and is used to transform the voltage on the secondary winding of the pulse transformer into a first preset voltage range when the voltage outputted by the secondary winding exceeds the first preset voltage range, and then output the voltage.

A DC-DC converter may include: a first converter for converting an input voltage to generate a first power supply voltage; a duty ratio controller configured generate a duty ratio control signal for controlling a duty ratio of a switching pulse of the first converter; a switching frequency controller configured to generate a switching frequency control signal for controlling a driving frequency of the first converter corresponding to a switching frequency of the switching pulse; and a current sensor configured to sense current flowing through the first converter. The first converter is driven at a switching frequency of a first frequency in a first mode, based on the switching frequency control signal, and generates the first power supply voltage of a first level, based on the duty ratio control signal. The switching frequency controller determines whether to turn off the current sensor.

Various embodiments include a DC coupled electrical converter for converting an input voltage applied to first connections to an output voltage comprising: a boost converter connected on the input side to the first connections; an inverting buck-boost converter connected on the input side to the first connections; and a series circuit including two capacitors, the series circuit connected to an output-side positive pole of the boost converter and to an output-side negative pole of the inverting buck-boost converter. An output-side negative pole of the boost converter and an output-side positive pole of the inverting buck-boost converter are connected to a center connection between the capacitors.

A method for energy harvesting is provided that uses an auxiliary energy storage device as a voltage source for the controller of a main voltage converter system. The auxiliary energy storage device is initially charged with a cold-start voltage converter and thereafter a main voltage converter system is charging a first rechargeable energy storage device until an upper charging threshold level is reached. The voltage of the auxiliary energy storage device is monitored and kept equal to a target value suitable for operating the controller, or alternatively within a predefined voltage range corresponding to the supply voltage range for the controller. A power management integrated circuit for energy harvesting is provided that includes a cold-start and a main voltage converter system, an internal voltage node is kept at a target value or within a voltage range suitable as a supply voltage for the controller.

A constant on time converter control circuit and a constant on time converter are provided. The constant on time converter control circuit comprises an error amplifier, a voltage to current converter, and an initial current source. The error amplifier is for receiving a reference voltage signal and a feedback voltage signal and outputting a compensated voltage signal. The voltage to current converter receives the compensated voltage signal and outputs a converted current signal. The initial current source provides an initial current signal. The initial current signal and the converted current signal form a new reference voltage signal. A constant on time OFF time comparator receives the new reference voltage signal and the feedback voltage signal and outputs a control signal. The control signal affects the turning on and turning off of electronic switches to produce an output voltage of a constant on time converter.

An audio amplifier with duty ratio control is provided. The audio amplifier comprises a pulse width modulation modulator, a power stage, and a voltage converter. The pulse width modulation modulator is configured to receive an input signal for generating a pulse width modulation signal. The power stage is configured to output an output signal according to a supply voltage and the pulse width modulation signal. The voltage converter is configured to adjust voltage level of the supply voltage according to the pulse width modulation signal. The audio amplifier is configured to adjust the voltage level of the supply voltage when duty ratio of the pulse width modulation signal is greater than a duty ratio threshold.