PULSE MODULATOR
A pulse modulator comprises a solid state power switch having a source, a drain, a gate and a separate gate drive connected to ground. One pulse modulator comprises a plurality of stages connected as an induction adder. Each stage includes a plurality of cells and at least some of the cells each include a solid state power switch having a source, a drain, a gate and a separate gate drive connected to ground to control the discharge of a capacitor. In one embodiment the solid state power switch is a power MOSFET.
1 . A pulse modulator comprising: a solid state power switch having a source, a drain, a gate and a separate gate drive connected to ground.
2 . The pulse modulator as claimed in claim 1 , wherein the solid state power switch comprises a plurality of solid state power switches, the pulse modulator further comprising a plurality of stages, each stage including a plurality of cells, and at least some of the cells each including a-at least one of the solid state power switches.
3 . The pulse modulator as claimed in claim 2 , wherein the plurality of stages is connected as an induction adder.
4 . The pulse modulator as claimed in claim 1 , wherein the solid state power switch is a power MOSFET.
5 . The pulse modulator as claimed in claim 2 wherein said at least some of the cells each include a gate driver and a balun, the gate driver being connected to the gate of the solid state power switch via the balun.
6 . The pulse modulator as claimed in claim 2 wherein said at least some of the cells each include a Zener diode via which the separate gate drive is connected to ground.
7 . The pulse modulator as claimed in claim 1 , further including a diode in series with the solid state power switch.
8 . The pulse modulator as claimed in claim 7 wherein the diode is a Schottky diode.
9 . The pulse modulator as claimed in claim 2 , wherein said at least some of the cells each include more than one of said solid state power switches having a source, a drain, a gate and a separate gate drive connected to ground.
10 . The pulse modulator as claimed in claim 2 , wherein each stage includes a magnetic induction core, a single turn primary winding and a single turn secondary winding and the secondary windings are connected in series.
11 . The pulse modulator as claimed in claim 2 , wherein said at least some of the cells each include a capacitor which is connected to be discharged by the solid state power switch to generate pulses.
12 . The pulse modulator as claimed in claim 1 , wherein the pulse modulator is operative to generate pulses having a pulse rise time of less than 5 ns and pulse length in the range 15 ns to 20 ns.
13 . The pulse modulator as claimed in claim 1 , wherein the pulse modulator is operative to generate pulses having repetition rate of greater than 1000 pps.
14 . The pulse modulator as claimed in claim 13 , wherein the pulse modulator is operative to generate pulses having repetition rate of greater than 1 megaHertz.
15 . The pulse modulator as claimed in claim 1 , wherein the pulse modulator is aoperative to generate pulses with a peak power of the order of tens of megawatts.
16 . The pulse modulator as claimed in claim 15 , wherein the pulse modulator is operative to generate pulses with a peak power in the range 30 to 40 MW.
17 . The pulse modulator as claimed in claim 2 , wherein each stage has dimensions of less than or equal to 120 mm×240 mm.
18 . The pulse modulator as claimed in claim 2 , wherein the cells of the plurality of cells are nominally identical.
19 . The pulse modulator as claimed in claim 2 , further including a non-linear snubber network to dissipate reflected energy in at least one of the cells.
20 . A system comprising a pulse modulator as claimed in claim 1 , further including a load, the pulse modulator being connected to apply pulses across the load.
21 . (canceled)