Three-terminal power mosfet switch for use as synchronous rectifier or voltage clamp
First Claim
1. A semiconductor device comprising:
- a source region of a first conductivity type;
a body region of a second conductivity type opposite to said first conductivity type adjacent said source region;
a drain region of said first conductivity type adjacent said body region, wherein said source region and said body region are connected together and biased at a first voltage and said drain region is biased at a second voltage, said first and second voltages being established such that a junction between said body region and said drain region is forward-biased;
a gate separated by an insulating layer from a channel region of said body region; and
a first switch for alternately connecting said gate to said source region or to a third voltage, said third voltage being sufficient to turn said semiconductor device fully on.
5 Assignments
0 Petitions
Accused Products
Abstract
An N-channel power MOSFET is fabricated with its source and body connected together and biased at a positive voltage with respect to its drain. The gate is controlled by a switch which alternately connects the gate to the source or to a voltage which turns the channel of the MOSFET fully on. When the gate is connected to the source, the device functions as a "pseudo-Schottky" diode which turns on at a lower voltage and provides a lower-resistance path than a conventional PN diode. When the gate is connected to the positive voltage the channel of the MOSFET is turned fully on. This MOSFET switch is particularly suitable for use as a synchronous rectifier in a power converter where it reduces the power loss and stored charge in the "break before make" interval (i.e., the interval between the turn-off of the shunt switch and the turn-on of the synchronous rectifier).
116 Citations
8 Claims
-
1. A semiconductor device comprising:
-
a source region of a first conductivity type; a body region of a second conductivity type opposite to said first conductivity type adjacent said source region; a drain region of said first conductivity type adjacent said body region, wherein said source region and said body region are connected together and biased at a first voltage and said drain region is biased at a second voltage, said first and second voltages being established such that a junction between said body region and said drain region is forward-biased; a gate separated by an insulating layer from a channel region of said body region; and a first switch for alternately connecting said gate to said source region or to a third voltage, said third voltage being sufficient to turn said semiconductor device fully on. - View Dependent Claims (2)
-
-
3. A power converter comprising:
-
a semiconductor device comprising; a source region of a first conductivity type; a body region of a second conductivity type opposite to said first conductivity type adjacent said source region; a drain region of said first conductivity type adjacent said body region, wherein said source region and said body region are connected together and biased at a first voltage and said drain region is biased at a second voltage, said first and second voltages being established such that a junction between said body region and said drain region is forward-biased; a gate separated by an insulating layer from a channel region of said body region; and a first switch for alternately connecting said gate to said source region or to a third voltage, said third voltage being sufficient to turn said semiconductor device fully on; said power converter further comprising; an inductor; and a second switch connected in series with said inductor; wherein said semiconductor device is connected to a common node between said inductor and said second switch. - View Dependent Claims (4, 5, 6, 7, 8)
-
Specification