Chengdu Monolithic Power Systems Co., Ltd.

Monolithic Power Systems, Inc.

Jiali Cai

Naixing Kuang

Lin Feng

Hongxia Yu

Yuancheng Ren

Xiaoyu Xi

Junming Zhang

Eric X Yang

Lei Du

Yongliang Zhang

An LED driving apparatus includes a rectifier bridge generating a DC bus voltage, a bus capacitor coupled between the output terminal of the rectifier bridge and a reference ground, a voltage sensing circuit generating a voltage sensing signal indicative of the DC bus voltage, a bleeding circuit providing a bleeding current for the bus capacitor, a switching converter configured to convert the DC bus voltage into a driving signal to drive an LED, a dimming mode detector detecting whether the LED driving apparatus is coupled to a leading edge dimmer or a trailing edge dimmer based on the voltage sensing signal, and a bleeding control circuit generating a control signal to control the bleeding circuit based on the voltage sensing signal, the leading edge dimming mode signal and the trailing edge dimming mode signal.

Dimmer compatible LED driving apparatus with adjustable bleeding current

An LED driving apparatus includes a rectifier bridge generating a DC bus voltage, a bus capacitor coupled between the output terminal of the rectifier bridge and a reference ground, a tank element, a first transistor, a second transistor, a free-wheeling switch, an output capacitor, a voltage sensing circuit generating a voltage sensing signal indicative of the DC bus voltage, a bleeding circuit providing a bleeding current for the bus capacitor, and a bleeding control circuit generating a control signal to control the bleeding circuit based on the voltage sensing signal.

Dimmer compatible LED driving apparatus with bleeding circuit

A dimming mode detection method is used in an LED driving apparatus including a rectifier bridge providing a DC bus voltage and a switching converter configured to convert the DC bus voltage into a driving signal to drive an LED. The method involves: powering on the LED driving apparatus; sensing the DC bus voltage and generating a voltage sensing signal; comparing a rising time during which the voltage sensing signal increases from a second threshold voltage to a first threshold voltage with a first time threshold to detect whether the LED driving apparatus is connected to a leading edge dimmer; and comparing a falling time during which the voltage sensing signal decreases from a third threshold voltage to a fourth threshold voltage with a second time threshold to detect whether the LED driving apparatus is connected to a trailing edge dimmer.

Dimming mode detection method used in LED driving apparatus

The present invention provides a controller used in a TRIAC dimmer compatible LED driver and method thereof. The controller comprises a dimming signal generator, a dimming signal processor and a switch control circuit. The dimming signal generator receives an AC chopped voltage from a TRIAC dimmer and generates a dimming signal with regulated duty cycle in accordance with the AC chopped voltage. The dimming signal processor is coupled to the dimming signal generator and generates a processed dimming signal in accordance with the dimming signal. The duty cycle of the processed dimming signal is a sum of a predetermined duty cycle and the duty cycle of the dimming signal. Based on the processed dimming signal and a feedback signal indicative of the current flowing through LED, the switch control circuit generates a control signal to control at least one switch in a switching converter.

TRIAC dimmer compatible LED driver and method thereof

In one embodiment, a switch mode power supply comprising a switch and a control circuit is disclosed. The control circuit may comprise a multi-function pin configured to receive a first current sampling signal and a first voltage sampling signal. A first comparing signal may be provided by comparing the first voltage sampling signal with a first threshold signal when the switch is turned OFF, and a second comparing signal may be provided by comparing the first current sampling signal with a second threshold signal when the switch is turned ON. The control circuit may be configured to control the switch in accordance with the first comparing signal and the second comparing signal.

Switch mode power supply and control method thereof

A fast startup switching converter having a first switch, a second switch, a third switch, a first capacitor, and a controller controlling the ON and OFF switching of the second and third switches. The first terminal of the first switch is coupled to the input terminal of the switching converter, the second terminal is coupled to the first terminal of the second switch. The first terminal of the third switch is coupled to the second terminal of the first switch and the first terminal of the second switch. The first capacitor is coupled to the second terminal of the third switch and the controller to provide a power supply voltage for the controller. The switching converter charges the first capacitor through the first and third switches in a first working state, and transfers energy to a load through the first and second switches in a second working state.

Fast startup switching converter and method thereof

A circuit for controlling the switch frequency of an inverter that strikes and drives fluorescent lamps is disclosed. The circuit comprises a frequency generator and an offset circuit. The offset circuit provides a current signal in response to the lamp status. The frequency generator provides a frequency control signal in respond to the current signal so as to control the switch frequency of the inverter. When the lamp is open, the switch frequency of the inverter is higher; when the lamp is lighted, the switch frequency of the inverter is lower.

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Hangzhou, China

Jiali Cai