On-Bright Electronics (Shanghai) Co., Ltd.

Qian Fang

Lieyi Fang

Cong Lan

Liqiang Zhu

Huawei Lv

Yuan Lin

Xiangkun Zhai

Zhilin Fan

Jun Zhou

Ke Zhao Li

Zhiliang Chen

Yaozhang Chen

Yun Sun

Penglin Yang

Ke Li

Lleyi Fang

System and method for controlling a bleeder current to increase a power factor of an LED lighting system without any TRIAC dimmer. For example, the system for controlling a bleeder current to increase a power factor of an LED lighting system without any TRIAC dimmer includes: a first current controller configured to receive a rectified voltage generated by a rectifier that directly receives an AC input voltage without through any TRIAC dimmer; and a second current controller configured to: control a light emitting diode current flowing through one or more light emitting diodes that receive the rectified voltage not clipped by any TRIAC dimmer; and generate a sensing voltage based at least in part upon the light emitting diode current, the sensing voltage representing the light emitting diode current in magnitude.

Systems and methods for controlling power factors of LED lighting systems

Controller and method for a power converter. For example, a controller for a power converter includes: a first drive signal generator configured to generate a first drive signal and output the first drive signal to a first transistor configured to receive an input voltage and related to a primary winding coupled to an auxiliary winding and a secondary winding related to an output voltage; a second drive signal generator configured to generate a second drive signal and output the second drive signal to a second transistor coupled to the first transistor and related to the primary winding; a demagnetization detector configured to generate a demagnetization signal based at least in part on a first voltage related to the auxiliary winding, the demagnetization signal indicating an end of a demagnetization process; and a first controller configured to generate a first control signal.

Switch-mode power converters with control of turning off transistors for zero-voltage switching

System and method for controlling turning on a first transistor and turning off a second transistor. For example, a system for controlling turning on a first transistor and turning off a second transistor includes: a logic signal generator configured to: process information associated with a first voltage related to a second voltage of a first auxiliary winding, the first auxiliary winding being coupled to a primary winding, a secondary winding, and a second auxiliary winding; generate a third voltage based on at least information associated with the first voltage, the third voltage indicating a first voltage difference from a drain terminal to a source terminal of a first transistor related to the primary winding; process information associated with the third voltage and a reference voltage; and change a logic signal from a first logic level to a second logic level.

Control systems and methods for turning off transistors associated with auxiliary windings and turning on transistors associated with primary windings

Controller and method for a power converter. For example, a controller for a power converter includes: a feedback detector configured to receive a feedback voltage, sample the feedback voltage, and generate a sampled voltage based at least in part on the feedback voltage, the sampled voltage being associated with one or more fluctuations in magnitude; a resistor selector configured to receive the sampled voltage and generate one or more control signals based at least in part on the one or more fluctuations associated with the sampled voltage; a variable resistor network configured to receive the one or more control signals, determine a network resistance based at least in part on the one or more control signals, and output a compensation voltage based at least in part on the network resistance; and a voltage generator connected to the variable resistor network and configured to receive the compensation voltage.

Systems and methods for resistance adjustment related to switch-mode power converters

Systems and methods for controlling power factors of led lighting systems

Systems and methods are provided for regulating a power converter. An example system controller includes: a driver configured to output a drive signal to a switch to affect a current flowing through an inductive winding of a power converter, the drive signal being associated with a switching period including an on-time period and an off-time period. The switch is closed in response to the drive signal during the on-time period. The switch is opened in response to the drive signal during the off-time period. A duty cycle is equal to a duration of the on-time period divided by a duration of the switching period. One minus the duty cycle is equal to a parameter. The system controller is configured to keep a multiplication product of the duty cycle, the parameter and the duration of the on-time period approximately constant.

Systems and methods for output current regulation in power conversion systems

Power converter and method thereof according to certain embodiments. For example, the power converter includes a primary winding, and a secondary winding coupled to the primary winding. Additionally, the power converter includes a first switch including a first switch terminal, a second switch terminal, and a third switch terminal. The first switch is configured to affect a first current associated with the primary winding. The first switch terminal corresponds to a first voltage, and the second switch terminal corresponds to a second voltage. The first voltage minus the second voltage is equal to a voltage difference. Moreover, the power converter includes a second switch including a fourth switch terminal, a fifth switch terminal, and a sixth switch terminal and configured to affect a second current associated with the secondary winding.

Systems and methods for reducing switching loss in power conversion systems

Systems and methods are provided for regulating power conversion systems. A system controller includes: a first controller terminal configured to receive a first signal related to an input signal for a primary winding of a power conversation system; and a second controller terminal configured to output a drive signal to a switch to affect a current flowing through the primary winding, the drive signal being associated with a switching period including an on-time period and an off-time period. The switch is closed (e.g., being turned on) in response to the drive signal during the on-time period. The switch is opened (e.g., being turned off) in response to the drive signal during the off-time period. A duty cycle is equal to a duration of the on-time period divided by a duration of the switching period. The system controller is configured to keep a multiplication product of the duty cycle and the duration of the on-time period approximately constant.

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Shanghai, China

Qian Fang