Cascoded rectifier
View Patent ↗A high voltage rectifier device exhibiting low forward resistance and fast switching time formed of a high voltage structure connected in a cascode configuration with a low voltage structure. The high voltage structure is a bidirectional normally on semiconductor switch have two pairs of gate and source terminals which shuts off if either of the gate terminals is reverse biased. The low voltage structure is a diode, preferably a Schottky or barrier diode. The device is advantageously formed as an integrated circuit. With one of the terminal pairs of the switch clamped to zero volts, the device behaves as a diode, or the second terminal pair can be employed to provide the functions of a three terminal controlled rectifier. Among other possible applications are integrated circuits using four of the devices as a bridge rectifier, and as an anti-parallel diode for connection with an IGBT.
1. A switched high voltage rectifier device including:
a low voltage structure comprised of a diode;
a high voltage structure comprised of a bidirectional normally on semiconductor switch, wherein the high and low voltage structures are connected in a cascode conflauration wherein:
a cathode terminal of the diode is connected to a first source terminal of the bidirectional switch;
an anode terminal of the diode is connected to a first gate terminal of the bidirectional switch, and to a signal input terminal; and
a second source terminal of the bidirectional switch is connected to a signal output terminal, and
a coupling structure is provided between the second source terminal and a second gate terminal of the bidirectional switch.
2. A device according to claim 1 , wherein the low and high voltage structures are fabricated on a common substrate and encapsulated to form an integrated circuit.
3. A device comprising four rectifier devices according to claim 1 , constructed and configured to function as a full bridge rectifier.
4. A device according to claim 1 , wherein the coupling structure is an externally controlled voltage source, whereby the device functions as a three terminal controlled rectifier.
5. A device according to claim 1 , wherein the low voltage structure is a Schottky or a barrier diode.
6. A device according to claim 1 , wherein the device is constructed and configured to function as a diode.
7. A device according to claim 1 , wherein the device is constructed and configured to function as a three terminal controlled rectifier.
8. A device according to claim 1 , wherein the coupling structure is a direct connection, whereby the device functions as a diode.
9. A bridge rectifier device comprising first, second, third, and fourth switched rectifier devices as described in claim 8 , wherein:
the input terminal of the first switched rectifier and the output terminal of the fourth switched rectifier are connected to a first bridge input terminal;
the input terminal of the second switched rectifier and the output terminal of the third switched rectifier are connected to a second bridge input terminal;
the output terminal of the first and second switched rectifiers are connected to a first bridge output terminal;
the input terminals of the third and fourth switched rectifiers are connected to a second bridge output terminal; and
the bridge rectifier device is adapted to receive an AC input voltage at the bridge input terminals, and to provide a full wave rectified DC voltage at the bridge output terminals.
10. A bridge rectifier device according to claim 9 , wherein the four rectifier devices are formed on a common substrate as part of a single integrated circuit.
11. A device according to claim 9 , wherein the coupling structure is a direct connection, whereby the device functions as a diode.
12. A device according to claim 8 , in combination with an IGBT, the IGBT having emiffer and collector terminals thereof connected to the anode and cathode terminals of the rectifier device in an antiparallel relationship.
13. A combined device according to claim 12 , wherein the rectifier device and the IGBT are formed on a common substrate as part of a single integrated circuit.
14. A bridge rectifier device comprising first, second, third, and fourth switched rectifier devices as described in claim 1 , wherein:
an anode terminal of the first switched rectifier and a cathode terminal of the fourth switched rectifier are connected to a first bridge input terminal;
an anode terminal of the second switched rectifier and a cathode terminal of the third switched rectifier are connected to a second bridge input terminal;
cathode terminals of the first and second switched rectifiers are connected to a first bridge output terminal;
anode terminals of the third and fourth switched rectifiers are connected to a second bridge output terminal; and
the bridge rectifier device is adapted to receive an AC input voltage at the bridge input terminals, and to provide a full wave rectified DC voltage at the bridge output terminals.
15. A bridge rectifier device according to claim 14 , wherein the four rectifier devices are formed on a common substrate as part of a single integrated circuit.
16. A circuit comprising a switched high voltage rectifier device including:
a low voltane structure comprised of a diode;
a high voltage structure comprised of a bidirectional normally on semiconductor switch,
wherein the high and low voltage structures are connected in a cascode configuration:
further comprising an IGBT, the IGBT having emitter and collector terminals thereof connected to anode and cathode terminals of the rectifier device in an antiparallel relationship.
17. A circuit according to claim 16 , wherein the rectifier device and the IGBT are formed on a common substrate as part of a single integrated circuit.