Monolithic Power Systems, Inc.

Zhejiang Dabong Technology Co., Ltd.

Jin Hu

Junming Zhang

Yuancheng Ren

James Copland Moyer

Yang Shi

Lei Du

Huanyu Lu

Zhijun Ye

Qing Xu

Quansong Wu

Yuanchang Ren

Embodiments of LED driver circuits and the associated methods are disclosed herein. In one embodiment, the LED driver circuit comprises a switch-mode converter, a controller, a feedback circuit, and a gating circuit. The feedback circuit includes a current balance circuit. The gating circuit is responsive to both a current feedback signal and a voltage feedback signal and is configured to select one of them as the feedback signal.

Power systems for driving light emitting diodes and associated methods of control

The present invention is generally related to an electronic ballast, an ignition control apparatus used therein and associated method of operation. In one embodiment, an electronic ballast comprising an inverter and an ignition control apparatus which comprises a stability monitoring circuit and a controlled ignition circuit. The inverter converts a DC input voltage into an AC voltage to drive a gas discharge lamp. The stability monitoring circuit monitors whether the DC input voltage is stable. The controlled ignition circuit is electrically coupled to the stability monitoring circuit and the lamp, ignites the lamp based on the monitoring result. The controlled ignition circuit does not ignite the gas discharge lamp until the DC input voltage becomes stable.

Ignition control apparatus used in electronic ballast and method thereof

A switching regulator with frequency limitation comprises a switch, a current sensing circuit, a voltage feedback circuit, a control circuit and a frequency limitation circuit. The current sensing circuit senses the current flowing through the switch and generating a current sensing signal representative of it. The voltage feedback circuit senses the output signal of the switching regulator and generates a feedback signal accordingly. The control circuit compares the current sensing signal with the feedback signal and turns off the switch based on the comparison result. The frequency limitation circuit is electrically coupled to the control circuit to limit the switching frequency of the switch.

Switching regulator with frequency limitation and method thereof

In accordance with the teachings described herein, systems and methods are provided for a switching mode power supply. In one example, the switching mode power supply may include a transformer, a switching circuit and a switching control circuit. The transformer receives a DC input voltage on a primary winding and generates a DC output voltage on a secondary winding. The switching circuit, which may include a MOSFET switch, is coupled to the transformer and is configured to switch the transformer on and off. The switching control circuit generates a switching control signal to control the switching circuit in order to regulate the DC output voltage of the transformer. The switching control circuit is configured to generate the switching control signal as a function of a timing signal having a varying frequency, wherein the varying frequency of the timing signal causes a switching frequency of the switching circuit to vary over a period of time in order to reduce electromagnetic interference caused by the switching circuit.

Switching mode power supply with a spectrum shaping circuit

A frequency limitation method used in quasi-resonant control of a switching regulator is disclosed. The switching frequency is limited through setting a minimum time limit, such as a minimum switching period or a minimum OFF time. The minimum time limit may be a first time limit or a second time limit. The minimum time limit is changed into another value if the minimum voltage point approaches the minimum time limit point, so as to eliminate the audible noise.

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Hangzhou, China

Jin Hu