Delta Electronics, Inc.

Delta Electronics (shanghai) Co., Ltd

Hong-Yuan Jin

Jian-Ping Ying

Hong-Jian Gan

Pei-Qing Hu

De-Sheng Guo

Jia-Le Dai

Yan Chen

A control circuit, control method used in a PFC circuit and the power source system thereof are disclosed herein. The control circuit comprises: a zero current detection circuit having a polarity detection circuit for outputting a first and a second digital signals and a signal conversion circuit for generating an analog signal; a feedback circuit for generating a driving pulse signal; and a pulse distribution circuit for distributing the driving pulse signal to a first and a second switches according to the first and the second digital signal. After a switch cycle, one of the first and the second switch performs an ON operation for the next switch cycle when the current flowing through the inductor decreases to a predetermined threshold value, wherein an ON time of the first switch is equal in each switch cycle, and an ON time of the second switch is equal in each switch cycle.

Control circuit, control method used in PFC circuit and power source system thereof

A DC/DC converter, a power converter and a control method thereof are disclosed, where the DC/DC converter includes an output circuit, a rectangular wave generator, a resonant tank, a detection unit and a control unit. The output circuit has a load. The rectangular wave generator converts an input voltage into at least one rectangular wave. The resonant tank provides a first voltage based on the rectangular wave for the output circuit. The detection unit detects a signal related to a state of the load. When the state of the load is light-load or a no-load, the control unit controls a working frequency or a duty ratio of the rectangular wave, so that the duty ratio of the rectangular wave is within a predetermined range, in which a voltage gain of the DC/DC converter is greater than another voltage gain under the condition of 50% duty ratio.

DC/DC converter, power converter and control method thereof

A power factor correction (PFC) circuit includes an AC power, a first bridge arm and a second bridge arm. The first bridge arm includes first and second switches connected in series with each other. A second terminal of the first switch is connected to a first terminal of the second switch, and coupled to a first end of the AC power via a first inductor. The second bridge arm includes third and fourth switches connected in series with each other. A second terminal of the third switch is connected to a first terminal of the fourth switch and a second end of the AC power. The third and fourth switches operate in ON/OFF states by use of a control signal having an operation frequency consistent with that of the AC power. The on-state resistance of the third and fourth switches is lower than that of the first or second switch.

Power factor correction circuit

A DC/DC converter, a power converter and a control method thereof are disclosed, where the DC/DC converter includes an output circuit having a load, a rectangular wave generator having a bridge arm, a resonant tank, a detection unit and a control unit. The bridge arm includes a first and a second switches connected each other. The detection unit detects a signal related to a state of the load. When the state of the load is a light-load or a no-load, the control unit controls ON/OFF state of the first and second switches by pulse width modulation mode to convert an input voltage into at least one rectangular wave for the resonant tank. A duty ratio of the first switch is within a first or second predetermined range, and a duty ratio of the second switch is complementary to the duty ratio of the first switch, whereby a voltage gain of the DC/DC converter is greater than 1.

A DC/DC converter, a power converter and a control method thereof are disclosed, wherein the DC/DC converter includes an output circuit, a rectangular wave generator, a resonant tank, a detection unit and a control unit. The output circuit has a load. The rectangular wave generator converts an input voltage into driving pulses. The resonant tank provides a first voltage based on the driving pulses for the output circuit. The detection unit detects a signal related to a state of the load. When the state of the load is a light-load or a no-load, the control unit controls the rectangular wave generator in a hiccup mode to reduce a ratio of a work period to a stop period, or makes that number of the driving pulses within the current work period is less than the number of the driving pulses when a duty ratio is 50%.

A control method for reducing audio noise is disclosed. The method includes the steps of: providing an input power source; providing a power source converter having a component with a mechanical resonant frequency, coupled to the input terminal or the output terminal of the power source converter; providing an output capacitor and a load connected in parallel therebetween; making the power source converter operate in a burst mode; and controlling the electrical energy transferred from the input terminal to the output terminal of the power source converter during an operating period of every burst cycle, so as to reduce the audio noise of the power source converter.

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Shanghai, China

Hong-Yuan Jin