Power factor correction circuit with soft switched boost converter
First Claim
Patent Images
1. A boost converter for a power factor correction circuit comprising:
- input means for receiving a rectified AC signal;
output means;
a first controllable switch, a first inductor, and a second controllable switch connected in series across said input means;
a first controller for controlling the first switch to have a variable ON time;
a second controller for controlling the second switch to have a fixed ON time;
a first diode between said first switch and said output means;
a first capacitor in parallel with said first switch;
a second capacitor in parallel with said second switch;
a second diode across said first switch, said first inductor and said first diode; and
a third diode across said second switch and said first inductor.
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Abstract
A boost converter for a power factor correction circuit having application in a DC power supply for telecommunication equipment. The boost converter has a pair of independently controlled switches such as MOSFET in series with an inductor. A capacitor is in parallel with each switch and the lossless resonant discharge of the capacitors by energy stored in the inductor eliminates switch losses at turn on. As a result the converter may be operated at higher frequencies, thereby reducing the size and cost of magnetic components in the power supply.
51 Citations
18 Claims
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1. A boost converter for a power factor correction circuit comprising:
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input means for receiving a rectified AC signal; output means; a first controllable switch, a first inductor, and a second controllable switch connected in series across said input means; a first controller for controlling the first switch to have a variable ON time; a second controller for controlling the second switch to have a fixed ON time; a first diode between said first switch and said output means; a first capacitor in parallel with said first switch; a second capacitor in parallel with said second switch; a second diode across said first switch, said first inductor and said first diode; and a third diode across said second switch and said first inductor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. In a power supply for telecommunications equipment a power factor correction circuit having a boost converter, said boost converter comprising:
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input means for receiving a rectified AC voltage; output means; first and second switch means serially connected to opposite ends of a first inductance means, the combination being connected across said input means; a first capacitor shunting said second switch means; a second capacitor shunting said second first switch means; a first controller means for controlling the first switch means to have a variable ON time; and a second controller means for controlling the second switch means to have a fixed ON time such that the respective on-time of each switch means is adjusted to generate a boosted DC output voltage. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A method of generating a boosted DC voltage from a rectified AC voltage comprising the steps of:
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supplying the rectified AC voltage to a boost converter having a boost inductor, a boost diode; and
first and second independently controllable switch means serially connected to opposing ends of an inductance means, each of the switch means having a shunt capacitor;controlling the first switch means to have a variable ON time; controlling the second switch means to have a fixed ON time; and controlling the on and off relationship of each of said first and second switch means as a function of the frequency of the rectified AC input to minimize the reverse recovery current of said boost diode. - View Dependent Claims (18)
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Specification