A simple control scheme for a single stage flyback LED driver

作者：Wang Jian Min; Wu Sen Tung; Yen Shang Chin; Lin Jing Yuan

来源：International Journal of Circuit Theory and Applications, 2015, 43(12): 1879-1898.

DOI：10.1002/cta.2045

• single stage flyback
• LED
• low total harmonic distortion
• CCM

This study proposes a simple control scheme for using single-stage flyback (SSF) converters in lighting source applications for LEDs. Among the advantages of the average current mode is an I/O current ripple that is only one-half of the critical conduction mode (CRM). This condition helps extend the output capacitor lifetime while lowering the input EMI capacitance input EMI capacitance. The SSF converter proposed in this study operates in continuous conduction mode (CCM). In addition, two sample-and-hold (S/H) circuits are placed at the output voltage loop and feed-forward path, respectively. Since these S/H circuits access the average output current and average feed-forward voltage, the LED driver is unaffected by the 120-Hz ripple noise, the total harmonic distortion (THD) is reduced, and the transient response of the output current is improved. Finally, the operation principles and design considerations of the studied LED driver are analyzed and discussed. A laboratory prototype is also designed and tested to verify the feasibility.

• 出版日期2015-12