Delta Electronics, Inc.

Hsien-Kai Wang

Yen-Wei Lin

Shang-Kay Yang

Chi-Hung Lin

Yu-Jie Lin

Guo-Hua Wang

A power converter includes a power factor correction (PFC) circuit and a controller. The controller acquires a switching frequency based on an instantaneous value of the input voltage, and acquires an upper limit frequency and a lower limit frequency based on an effective value of an input current. When the controller determines that the effective value is greater than a medium load threshold, an operation mode of the PFC circuit is switched from a critical conduction mode or a triangular current mode to a continuous conduction mode based on the switching frequency being less than the lower limit frequency, and to limit the switching frequency to the lower limit frequency. Furthermore, the controller adjusts the lower limit frequency between a first lower limit frequency and a second lower limit frequency based on the increase or decrease of the effective value.

Power converter and method of operating the same

A power converter with reduced power consumption receives an input voltage and provides an output voltage to supply power to a load. The power converter includes a power factor correction circuit, a driver circuit, and a controller. The power factor correction circuit includes at least one inductor and an output capacitor. When the controller determines that an effective value of an input current is correspondingly lower than a current lower limit, a specific time period starts based on the output voltage reaching a voltage lower limit, and the specific time period ends based on the output voltage reaching a voltage upper limit. In the specific time period, the controller enables the driver circuit based on the input current being correspondingly greater than a predetermined threshold so as to continuously transfer the energy stored in the at least one inductor to the output capacitor.

Power converter with reduced power consumption and method of operating the same

A bridge converter converts an input voltage into an output voltage, and includes a switching circuit, a transformer, a rectifying circuit, and a control module. The switching circuit includes a first switch and a second switch. The control module sets a first time period and a second time period. The control module provides a first control signal and a second control signal to control the switching circuit based on the output voltage. The control module fixes an operation frequency of the first control signal and the second control signal at the maximum frequency based on that the control module is set in a standby mode, and provides the first control signal and the second control signal in the first time period, and shields the first control signal and the second control signal in the second time period.

Bridge converter and method of controlling the same

A power supply system with dynamic current sharing includes a current-sharing bus and a plurality of power supply units connected to each other through the current-sharing bus. The current-sharing bus provides a first current signal. Each power supply unit includes a local current bus for providing a second current signal. The active current-sharing unit compares the first current signal with the second current signal to generate a compensation voltage. The current-averaging unit compares a difference value between an average value of the first current signal and an average value of the second current signal to generate an average voltage. The droop current unit receives the second current signal to generate a droop compensation voltage. The integration calculation unit makes output currents of the power supply units be approximately equal according to the compensation voltage, the average voltage, and the droop compensation voltage.

Power supply unit and power supply system with dynamic current sharing

An LLC resonant converter includes a transformer and a primary-side circuit coupled to the transformer. The primary-side circuit includes a first bridge arm, a second bridge arm, and a control unit. The first bridge arm includes a first switch and a second switch, and the second bridge arm includes a third switch and a fourth switch. The control unit provides a first control signal to control the first switch and provides a fourth control signal to control the fourth switch. The control unit adjusts a switching frequency of the first control signal and the fourth control signal according to an output voltage. When the switching frequency increases to a frequency threshold value, the switching frequency is controlled to be fixed at the frequency threshold, and the first control signal and the fourth control signal are controlled to have a variable phase difference.

LLC resonant converter and method of controlling the same

An LLC resonance converter includes a switching circuit, a resonance tank, a transformer, a synchronous rectification unit, and a control unit. The switching circuit includes a first switch controlled by a first control signal and a second switch controlled by a second control signal. The synchronous rectification unit includes a first synchronous rectification switch controlled by a first rectification control signal and a second synchronous rectification switch controlled by a second rectification control signal. The first control signal, the first rectification control signal, the second control signal, and the second rectification control signal include an operation frequency and a phase shift amount. When the operating frequency is lower to a specific value or the phase shift amount is higher to a specific value, the control unit fixes one of them to extend a hold-up time of the LLC resonance converter.

LLC resonance converter and method of controlling the same

An LLC resonant converter includes a square wave generator having a first switch and a second switch, a resonant tank, a transformer, a synchronous rectifying (SR) unit having a first SR switch and a second SR switch, and a control unit. The control unit provides a first control signal controls the first switch, a second control signal controls the second switch, a first rectifying control signal controls the first SR switch, a second rectifying control signal controls the second SR switch. When a frequency control command is lower than a phase-shift frequency, the first control signal and the first rectifying control signal are frequency-variable and phase-shifted, and the second control signal and the second rectifying control signal are frequency-variable and phase-shifted.

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Taoyuan, Taiwan

Hsien-Kai Wang