To reduce energy losses for a welding device when on stand-by and to enable a clean and controlled start of the welding phase, a DC-to-DC converter of the welding device converts an input DC voltage present at an input connection to an output DC voltage present at an output connection. At least one switch element of a branch of the DC-to-DC converter is switched with a switching frequency, and a welding phase is provided for the welding device, during which the switching frequency corresponds to a normal switching frequency. A stand-by phase is provided for the welding device, during which the at least one switch element is switched with a switching frequency corresponding to a stand-by switching frequency which is lower than the normal switching frequency

A short-circuit protection circuit, chip and system for a switched-mode power supply are disclosed. The short-circuit protection circuit includes: a sampling module for sampling an input voltage and producing a first voltage from the input voltage; a generation module for generating a second voltage from a reference voltage; a comparison module for comparing the first voltage and the second voltage; and an output module for producing, from a result of the comparison performed by the comparison module, and outputting a control signal for controlling an external power transistor in the event of a short circuit in the switched-mode power supply. According to the present invention, when an output short circuit is detected, a hiccup-mode duty cycle is adjusted according to the input voltage, thus avoiding great energy loss when the input voltage is high and enabling loaded startup or automatic output recovery after the short circuit condition is removed when the input voltage is low.

Disclosed is a converter circuit having high power in an ultra-wide range, which includes a transformer module, a first and second primary input modules, an output module, a high and low voltage mode control module, and a load output module. The first primary input module includes a first primary voltage equalization network, a first switch module and a first LC module, the second primary input module includes a second primary voltage equalization network, a second switch module and a second LC module. The first primary voltage equalization network is connected between a first input capacitor and the second switch module, and the second primary voltage equalization network is connected between a second input capacitor and the first switch module. In this disclosure, it is surprisingly found that through arranging resonant voltage equalization network, a designated primary voltage deviation problem, which is caused by a change of a pulse control of an LLC resonant converter under a light load, is solved.

A power converter circuit may include a control circuit configured to generate a drive signal for rendering a semiconductor switch conductive and non-conductive to generate a bus voltage across a bus capacitor. The control circuit may adjust a minimum operating period of the drive signal to a first value when an output power of the power converter circuit is greater than a first threshold and to a second value when the output power is less than a second threshold. The control circuit may comprise a comparator that generates the drive signal in response to a sense voltage and a threshold voltage. When operating in a standby mode, the control circuit may adjust a magnitude of the threshold voltage based on an instantaneous magnitude of an alternating-current line voltage received by the power converter circuit, such that an input current drawn by the power converter circuit is sinusoidal.

A SIMO power converter includes: a power stage having an inductor and a plurality of switches, the power stage generating a plurality of output voltages from an input voltage; a control circuit, the control circuit controlling the SIMO power converter to be operated at either an OPDC (Ordered Power Distributive Control) mode or a Peak Current Control (PCC) mode according with different loading conditions, the control circuit further generating a plurality of duty cycles based on an inductor current of the inductor and the plurality of output voltages; and a logic control and gate driver for generating a plurality of switch control signals based on the duty cycles from the control circuit, the plurality of switch control signals for controlling the plurality of switches of the power stage.

Systems and methods for voltage regulation of high voltage direct current systems are provided. In certain embodiments, a system includes a generator that generates alternating current (AC) voltage. The system further includes a power converter that converts the AC voltage into regulated direct current (DC) voltage. Also, the system includes a voltage regulator. In additional embodiments, the voltage regulator includes an AC voltage regulator that regulates the AC voltage generated by the generator. Also, the voltage regulator includes a DC voltage regulator that regulates the DC voltage produced by the power converter. Moreover, the voltage regulator includes a regulator selector that selectively activates one of the AC voltage regulator and the DC voltage regulator based on a current from the power converter and at least one of a voltage of the generator and a voltage of the power converter.

A circuit for a multi-phase power regulator including a power stage with a first phase and a second phase, the circuit including phase management circuitry coupled to the first phase and the second phase to control the first phase and the second phase, a first comparator coupled to an output of the multi-phase power regulator to compare a value of the output of the multi-phase power regulator to a first threshold value to produce a first comparison result, and phase shedding circuitry coupled to the first comparator and the phase management circuitry to control the phase management circuitry to activate or deactivate the second phase based at least partially on the first comparison result.

An apparatus, such as an image forming apparatus, includes a Universal Serial Bus (USB) host interface configured to connect to a USB device, a direct current to direct current (DC-DC) converter configured to supply power to the USB device connected to the USB host interface, and a control unit configured to switch the DC-DC converter from a pulse width modulation (PWM) mode to a pulse frequency modulation (PFM) mode based on a type of the USB device connected to the USB host interface.

Provided is a maximum power point tracking (MPPT) apparatus for an energy harvesting system and an MPPT control method. A count value of the time for an output voltage of a direct current (DC)-DC converter to reach a high reference voltage is used to change and output a control parameter of the DC-DC converter for maximum power.

In some examples, a device for controlling a transistor in a power converter system includes a first circuit configured to generate an error current based on a difference between a reference signal and a feedback signal, where the feedback signal depends on an output voltage of the power converter system. The device also includes a frequency generator configured to generate an activation signal based on the difference between the reference signal and the feedback signal. The device further includes a pedestal circuit configured to define a peak current threshold for the transistor based on an offset value. The device also includes a logic circuit configured to activate the transistor based on the activation signal and deactivate the transistor when a current sense signal reaches the defined peak current threshold, where the current sense signal is representative of a power current conducted by the transistor.