Power circuit switching device having a passive protection circuit
A power circuit switching device comprises two switching terminals, a high-voltage depletion mode transistor and a low-voltage enhancement mode transistor arranged in series between the two switching terminals, a first terminal for receiving a switching signal and electrically connected via a driver circuit to the gate of the high-voltage transistor, and a second terminal for receiving a control signal and electrically connected to the gate of the low-voltage transistor. The device comprises a normally-on protection circuit electrically connected between the second terminal and the gate of the high-voltage transistor to keep the high-voltage transistor in an off-state when the driver circuit is not electrically powered.
1. A power circuit switching device comprising:
two switching terminals;
a high-voltage depletion mode transistor and a low-voltage enhancement mode transistor arranged in series between the two switching terminals, the avalanche voltage of the low-voltage transistor being lower than the avalanche voltage of the high-voltage transistor;
a first terminal for receiving a switching signal, electrically connected via a driver circuit to a gate of the high-voltage transistor;
a second terminal for receiving a control signal, electrically connected to the gate of the low-voltage transistor;
a normally-on protection circuit electrically connected between the second terminal and the gate of the high-voltage transistor to keep the high-voltage transistor in an off-state when the driver circuit is not electrically powered; and
a control device electrically connected to the first terminal and the second terminal for processing the control signal and selectively transmitting the switching signal.
2. The switching device according to claim 1 , wherein the protection circuit comprises a bipolar transistor and a resistor placed in an emitter of the bipolar transistor.
3. The switching device according to claim 2 , wherein the base of the bipolar transistor is electrically connected to the second terminal, a collector of the bipolar transistor is electrically connected to the ground of the device and the resistor is electrically connected to the gate of the high-voltage transistor.
4. The switching device according to claim 3 , wherein the protection circuit includes a second resistor between the second terminal and the ground of the device.
5. The switching device according to claim 4 , wherein a source of the high-voltage transistor is electrically connected to the drain of the low-voltage transistor.
6. The switching device according to claim 5 , wherein the high-voltage transistor is a GaN- or SiC-based HEMT transistor.
7. The switching device according to claim 6 , wherein the low-voltage transistor is a silicon-based MOSFET transistor.
8. The switching device according to claim 7 , wherein the avalanche voltage of the high-voltage transistor is greater than 600V.
9. The switching device according to claim 8 , further comprising a control device electrically connected to the first terminal and the second terminal for processing the control signal and selectively transmitting the switching signal.
10. The switching device according to claim 9 , wherein the driver circuit is electrically powered by at least one supply voltage source (VDR+, VDR−).
11. The switching device according to claim 10 , wherein the control device is electrically connected to the at least one supply voltage source for selectively switching it on or off.
12. The switching device according to claim 2 , wherein the protection circuit includes a second resistor between the second terminal and the ground of the device.
13. The switching device according to claim 1 , wherein a source of the high-voltage transistor is electrically connected to the drain of the low-voltage transistor.
14. The switching device according to claim 1 , wherein the high-voltage transistor is a GaN- or SiC-based HEMT transistor.
15. The switching device according to claim 1 , wherein the low-voltage transistor is a silicon-based MOSFET transistor.
16. The switching device according to claim 1 , wherein the avalanche voltage of the high-voltage transistor is greater than 600V.
17. The switching device according to claim 1 , wherein the driver circuit is electrically powered by at least one supply voltage source (VDR+, VDR−).
18. The switching device according to claim 17 , wherein the control device is electrically connected to the at least one supply voltage source for selectively switching it on or off.
19. A power circuit switching device comprising:
two switching terminals;
a high-voltage depletion mode transistor and a low-voltage enhancement mode transistor arranged in series between the two switching terminals, an avalanche voltage of the low-voltage transistor being lower than the avalanche voltage of the high-voltage transistor;
a first terminal for receiving a switching signal, electrically connected via a driver circuit to a gate of the high-voltage transistor;
a second terminal for receiving a control signal, electrically connected to the gate of the low-voltage transistor; and
a normally-on protection circuit electrically connected between the second terminal and the gate of the high-voltage transistor to keep the high-voltage transistor in an off-state when the driver circuit is not electrically powered, the normally-on protection circuit comprising a bipolar transistor and a resistor placed in an emitter of the bipolar transistor.