A constant current LED driver based on flyback structure with novel primary side control

A primary side control LED driver with a novel constant current control mechanism is proposed in this paper. In order to simplify the peripheral circuits, the proposed driver employs two cascaded power MOSFETs to eliminate auxiliary winding. The resonance occurs in the transformer will couple to the connection of power MOSFETs. Thus the system can obtain the demagnetization information by sampling the resonance. Based on this, the system can output constant current by adopting charging and discharging module. The control IC has been designed in CSMC's 0.8-μm 600V process. Simulation results show that the average output current precision is within +4.7% and the demagnetization time detection error is less than 0.2%.

[1]  Xiliang Chen,et al.  Evaluation of primary side control schemes for flyback converter with constant current output , 2013, 2013 Twenty-Eighth Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[2]  Lenian He,et al.  A primary side feedback control for flyback LED driver with no output voltage feedback resistors , 2014, 2014 International Symposium on Integrated Circuits (ISIC).

[3]  Xiaogao Xie,et al.  A Novel Output Current Estimation and Regulation Circuit for Primary Side Controlled High Power Factor Single-Stage Flyback LED Driver , 2012, IEEE Transactions on Power Electronics.

[4]  Qi Zheng,et al.  Constant current LED driver based on flyback structure with primary side control , 2011, 2011 IEEE Power Engineering and Automation Conference.

[5]  Andrea Baschirotto,et al.  A 0.18-µm CMOS, 91%-Efficiency, 2-A Scalable Buck-Boost DC–DC Converter for LED Drivers , 2014, IEEE Transactions on Power Electronics.