US 5,956,243 AGranted

Three-level boost rectifier with voltage doubling switch

AssigneeLucent Technologies Inc.

InventorHengchun Mao

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Abstract

An three-level boost rectifier circuit is described for universal line applications. The boost rectifier circuit includes a boost inductor connected to the input voltage. A bridge rectifier composed of four diodes is connected between the boost inductor and two output capacitors. Two boost switches, each with two series diodes are connected between the bridge diodes and the output capacitors. A threshold switch is connected between the bridge diodes and the output capacitors. The threshold switch is closed when the input voltage is below a predetermined threshold voltage and opened when the input is above the threshold voltage. Closing the threshold switch acts to reverse bias two of the four bridge diodes, reducing the number of diodes conducting at any given moment to one. This reduces the conduction losses of the circuit at low input voltage, making the circuit more efficient at low-line inputs. Further, the configuration of the boost rectifier circuit of the present invention reduces the required voltage rating for the boost switches, making the boost switches more efficient when conducting current.

Claims14

Dependent claims

A boost rectifier for producing a dc output voltage from an input current generated by a power source, the boost rectifier comprising:

a) a boost inductor connected to the power source;
b) four bridge diodes connected to the boost inductor and the power source to rectify the ac input current from the power source;
c) a first boost switch connected in series with a first and second series diodes which are connected to the bridge diodes, the boost switch regulating the dc output voltage;
d) a second boost switch connected in series with a third and fourth series diodes and connected to the boost rectifier in the same manner as the first boost switch and the first and second series diodes;
e) two output capacitors connected to the bridge diodes and the first and second boost switches, wherein the dc output voltage is developed across the two output capacitors;
and
f) a threshold switch connected between the two output capacitors and the bridge diodes, the threshold switch operable between a closed position when the amplitude of the input voltage is below a threshold and an open position when the amplitude of the input voltage is above the threshold, wherein the threshold switch when in the closed position reverse biases two of the bridge diodes, such that when the amplitude of the input voltage is below the threshold, no more than one diode in the boost rectifier is conducting current, and such that both the first and second boost switches are operable when the threshold switch is closed.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/133,067Filed 12 Aug 1998
Granted: 21 Sep 1999
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H02M 1/4208
Circuits or arrangements for compensating for or adjusting power factor in converters or inverters: arrangements for improving power factor of AC…
H02M 7/25
Using semiconductor devices only: arranged for operation in series, e.g. for multiplication of voltage
Y02B 70/10
Technologies for an efficient end-user side electric power management and consumption: technologies improving the efficiency by using…
H02M
Apparatus for conversion between ac and ac, between ac and dc, or