| 摘要 |
<p>Disclosed is a low-cost PFC converter configurated such that the inductor current including a direct current component is detected and the power factor is appropriately improved with low loss. It is provided with a diode bridge (B1) that rectifies alternating current voltage input from an alternating current power source (Vac), a series circuit that includes an inductor (L1) and a switching element (Q1), a rectification smoothing circuit connected in parallel with the switching element (Q1) and comprised of a diode (D1) and a smoothing condenser (C1), and a digital signal processing circuit (13) that controls turning switching element (Q1) on/off such that the current input from the alternating current power source (Vac) is similar in shape to an alternating current voltage. The current flowing in inductor (L1) while switching element (Q1) is off is detected by means of a current detection resistor (R1), the falling voltage of the current detection resistor (R1) is sampled in the middle of the off period for switching element (Q1), and the average value of the input current is detected.</p> |
