Joulwatt Technology (hangzhou) Co., Ltd.

Joulwatt Technology Co., Ltd.

Hangzhou Xieneng Technology Co., Ltd.

Joulwatt Technology Inc. Limited

Joulwatt Technology (shenzhen) Co., Ltd.

Pitleong Wong

Xunwei Zhou

Yuancheng Ren

Siopang Chan

Junming Zhang

Guoqiang Liu

Feng Xu

Xianghua Jiang

Yang Lu

Yue Ji

Duo Li

Liyu Lin

Yang Yang

Yiqing Jin

Xiangyong Xu

Yingyan He

Aimin Xu

Mengyi Huang

Danji Xi

Yang Cheng

Shengfeng Li

Jianyu Xie

Libin Huang

Yongan Huang

Weijun Mao

Zhirong Chen

Bai Lang

Disclosed is a high-efficiency flyback converter and a control method thereof. The flyback converter comprises: a transformer; a first switch transistor and a second switch transistor; a resonant capacitor; a control circuit, for controlling the second switch transistor to be turned on for a first time before the first switch transistor is turned on during a switching cycle, controlling the second switch transistor to maintain turn-off state during a first time stage, to control energy transmission between primary and secondary sides to include two time stages during a switching cycle, the first time stage lasts for a set time period during a freewheeling process. The present disclosure allows the main switch transistor to realize zero-voltage turn-on, thus reducing conduction loss of the primary and the secondary sides, reducing ripples of an output voltage and a current of the secondary side, and being beneficial to improving operating efficiency.

Flyback converter with high efficiency and control method thereof

Disclosed is a power conversion circuit for quick response and a switching power supply, wherein an error compensation signal is obtained according to a sampled signal representing an output feedback signal or an average current through the inductor. A PWM control signal is generated according to the error compensation signal, a ramp signal, and a proportional signal, and is used to control switching operations of a main power switch transistor, the proportional signal is proportional to an input voltage or/and an output voltage, thus the system can quickly respond to transient change of the input voltage or the output signal and provide stable output. Output voltage information or/and input voltage information can be fed back to a control loop, thus the system can quickly obtain a switching duty cycle which allows the system to operate in a state close to steady, and dynamic response speed of the system is fast.

Power conversion circuit for quick response and switching power supply

The present application discloses a switching frequency synchronization circuit, a method therefor and a switching power supply. By comparing peak values of a second charging voltage signal which represents an internal clock signal and a first charging voltage signal which represents an external clock signal, it is determined whether the frequency of the external clock signal meets the requirement for frequency synchronization. In a case that the frequency meets the requirement, the second charging voltage signal is reset by the external clock signal to synchronize the frequency of the internal clock signal with the frequency of the external clock signal. The present disclosure does not need a complex phase-locked loop circuit, and adjust an internal clock frequency by simple voltage comparison and synchronization mode. The control circuit is simplified and the overall system cost is reduced.

Switching frequency synchronization circuit, method therefor and switching power supply

Disclosed is an LED driver circuit, a multi-wire communication device and a method for an LED display system. The device comprises a controller providing at least one of a configuration data packet, a brightness data packet, and a display data packet; the LED driver circuits, wherein the LED driver circuits are cascaded to provide a first data channel using first data ports and second data ports, the LED driver circuits are connected in parallel to provide a second data channel using third data ports. The device relays an enable signal or an address data packet stage by stage using the first data channel, transmit at least one of the configuration data packet, the brightness data packet and the display data packet in parallel using the second data channel. The number of the cascaded LED driver circuits can be infinite, the number of data wires is reduced, data rate is increased.

LED driver circuit, multi-wire communication device and method for LED display system

A control circuit and control method for a switched capacitor converter (SCC) are provided. An adjustment circuit makes adjustment with a small pull-down current, such that two terminal voltages of a flying capacitor are consistent with an output voltage. Before the SCC works formally for voltage conversion, the two terminal voltages of the flying capacitor are the same as the output voltage.

Control circuit and control method for switched capacitor converter

A supply circuit and a switched mode power supply (SMPS) are provided. The supply circuit includes a first capacitor, a second capacitor, and a charging-discharging control circuit; the first capacitor includes a first terminal connected to a switching node, and a second terminal for providing a first supply voltage; the second capacitor includes a first terminal connected to a reference ground or a first potential terminal under control of the charging-discharging control circuit, and a second terminal for providing a second supply voltage; and according to a charging-discharging enable signal, the charging-discharging control circuit charges the second capacitor in a first time period and discharges the second capacitor in a second time period.

Supply circuit and switched mode power supply

A dimming method and a dimming circuit for driving LED load are provided. The dimming circuit includes a power stage circuit, and the power stage circuit includes a power switch transistor. After the power stage circuit enters the DCM working mode, it obtains a first integral value according to the inductance current in a switch period of the power switch transistor, and obtains second time according to the first integral value and a duty cycle of a PWM dimming signal; when the switch period reaches the second time, the power switch transistor is controlled to be turned on to start the next switch period; a first upper limit voltage is set to a fixed voltage; the power switch transistor is controlled to be turned off when a sampling signal of the inductance current representing the inductance current of the power stage circuit reaches the first upper limit voltage.

Dimming method and dimming circuit

A dynamic automotive turn signal circuit includes at least one drive control module configured to receive a power supply signal from a body control module (BCM) to start operation, where the drive control module outputs first control signals at different delays through a delay unit; and a light emitting diode (LED) light set connected to the drive control module and lit based on the first control signals. A dynamic automotive turn signal system is further provided. The dynamic automotive turn signal circuit and the dynamic automotive turn signal system uses an external resistor to preset a high-precision delay circuit to realize the function of dynamic flowing turn signals. The external resistor can be used to configure a turn-on delay and a turn-off delay of the internal driver chip, such that the channel turn-on time and turn-off time can be flexibly adjusted.

Dynamic automotive turn signal circuit and dynamic automotive turn signal system

A light source driving circuit and a communication device for a display system are provided. The communication device includes a control unit and at least one string light source driving circuit. The control unit includes an output interface for transmitting the control commands or data and a reading back data input interface. Each string light source driving circuit includes a plurality of light source driving circuits. The control unit transmits the control commands or data to the first light source driving circuit of each string light source driving circuit through the output interface. The first driving circuit takes out the commands or data required at the current stage after receiving the control command or data, and then repackages the commands or data of the remaining driving circuits, and transmits the repackaged data packet through the serial output interface and the parallel interfaces or the parallel interfaces.

Light source driving circuit and communication device for display system

A light source driving circuit and a communication device for display system are provided. The communication device includes a control unit and at least one string light source driving circuit. The control unit includes an output interface for transmitting control commands or data and a data reading back input interface. Each string light source driving circuit includes a plurality of light source driving circuits, and each light source driving circuit interface includes a serial input interface, a serial output interface, parallel interfaces, and at least one current output interface. The serial input interface and serial output interface of the plurality of light source driving circuits are cascaded with each other as a first channel of the control commands or data transmission. The parallel interfaces of each driving circuit in the plurality of driving circuits are coupled with each other as a second channel of the control commands and data transmission.

An X-capacitor discharge method applied to a switched-mode power supply, wherein the switched-mode power supply comprises an X-capacitor, a rectifier circuit and a switching circuit; the X-capacitor discharge method comprises: arranging a first diode, wherein an anode of the first diode is connected to a first end of the X-capacitor, and a cathode of the first diode is configured as a first node; when it is detected that a voltage of the first node is higher than a first voltage threshold, pulling down the first node through a first sampling current, and performing a timing; and if a time for which the voltage of the first node continues to be higher than the first voltage threshold reaches a first threshold time, pulling down the first node through a first pull-down current. An X-capacitor discharge circuit applied to the switched-mode power supply is provided.

X-capacitor discharge method, X-capacitor discharge circuit and switched-mode power supply

A flyback switching circuit and control method thereof is disclosed, by setting a reference value greater than zero configured for controlling a turn-off time of a first transistor of the flyback switching circuit, a drain-source voltage of a main power transistor of the flyback switching circuit is consistent with the reference value greater than zero before the main power transistor is turned on, so that a turn-on power consumption of the main power transistor is reduced and a system efficiency is improved.

Flyback switch circuit and control method thereof

The present disclosure provides a power transistor driving method. When a power transistor is turned off, a drain-source voltage of the power transistor is detected, and when the power transistor is an N-type component, and a change rate of the drain-source voltage of the power transistor along with time is lower than a first slope threshold, the power transistor is pulled down in a first current; when the change rate of the drain-source voltage of the power transistor along with the time is higher than the first slope threshold, a driving pole of the power transistor is pulled down in a second current; and when the change rate of the drain-source voltage of the power transistor along with the time is lower than the first slope threshold again, a pull-down switch is turned on or the driving pole of the power transistor is pulled down in a third current.

Power transistor driving method, driving circuit and switching circuit

The present disclosure provides a power transistor driving method, a driving circuit and a switching circuit. When the power transistor is an N-type component, a driving pole of the power transistor is pulled down in a first current, and when a time period recorded by the timer reaches a first time period, a pull-down switch is turned on or the driving pole of the power transistor is pulled down in a second current; the driving pole of the power transistor is pulled down by the pull-down switch; when a timer is started from a moment at which the power transistor is turned off, the first time period is higher than a time period from a moment at which a switching tube is turned off to a moment at which the change rate of the drain-source voltage of the power transistor along with the time is higher than the first slope.

A clamping switch abnormality detection method, a clamping switch abnormality detection circuit and a switch circuit are provided, wherein an active clamping flyback circuit includes a clamping switch, a main switch and a transformer. When a clamping switch control signal is active, a switching node voltage or a voltage on an auxiliary winding or an magnetizing inductor current is detected, and when the switching node voltage or the voltage on the auxiliary winding or the magnetizing inductor current oscillates, or the switching node voltage is less than a first voltage threshold or the voltage on the auxiliary winding is less than a second voltage threshold, the clamping switch is abnormal or a clamping switch driving circuit is abnormal. The switching node is a common node of the transformer and the main switch, and the transformer includes a primary winding, a secondary winding and the auxiliary winding.

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Hangzhou, China

Pitleong Wong