| 摘要 |
A power supply provides a regulated power factor load to a primary power source, and thus low input current distortion, by monitoring: (A) The input voltage; (B) The power source current, not at the input to the power supply, but rather at a point downstream of an EMI filter and a shunt capacitance in the power supply; and (C) The output DC voltage. The power supply uses these inputs to control the power switching transistors to regulate the phase and amplitude of the monitored current. The phase of the monitored current is controlled primarily by the phase of the input voltage. A differentiating circuit in the feedback loop of the power supply control circuitry causes the monitored current to lag the input voltage by an amount equal to the lead induced in the phase of the input current by the EMI filter and shunt capacitor so that the actual input current to the power supply is in phase with the input voltage.
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