| Popis: |
This paper presents an offline current-mode pulse frequency modulation (PFM) controller for low power residential LED lighting, which has a better performance and a simplified structure. A novel controller which contains Constant Current (CC) regulation technique based on auxiliary winding feedback and pulse frequency modulation (PFM) mode basing on the flyback structure is presented, which simplifies the application environment. Also, an input power adjusting technique is introduced which improves the working stability. These techniques are validated by using an integrated circuit designed in 0.5-μm 700V BCD process. In the constant area, when the input AC voltage is from 85V-220V and the load resistance is from 3Ω to 4.7Ω, the test results of actual application circuit show the constant current point is about 1A and the current ripple is about ±4%. |
