| 摘要 |
A one cycle control method for power factor correction based on a boost circuit and a main control chip of system comprises the steps of: (1) Determining whether soft-start ends or not; if the soft-start ends, processing step (2) directly, if not, increasing reference value Uref of output voltage and then processing step (2); (2) Reading sampling output voltage Uo, and sampling inductive current ig according to A/D sampling triggering instant; (3) Calculating duty ratio of PWM signal for driving the switch transistor; (4) Outputting PWM signal; (5) Calculating the next A/D sampling triggering instant according to the duty ratio of PWM signal; (6) Returning to step (2). The present invention can implement the function of power factor correction by integrating the software of the method into the main control chip of the existing system and cooperating with the simple boost circuit, without using the traditional circuit for power factor correction and the specific one cycle control chip for PFC, which reduces the cost of the system. Also the present invention ensures the sampling data true and correct, and the stable operation of system, by simple processing of the sampling triggering instant.
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