Pulse generator
View Patent ↗A pulse shaping device includes an inductor that is selectively output-coupled to a first port of a capacitor. The inductor is charged to a selected current throughput and then coupled to the first port to generate a first characteristic within the current flowing at a second port of the capacitor. The capacitor is charged until reaching a clamping voltage at the first port. A voltage clamp of the shaping device clamps the first port of the capacitor at the clamping voltage to generate a second characteristic within the current flowing at a second port of the capacitor.
1. A method including:
charging an inductor to a selected current throughput;
at a time that the inductor is charged to the selected current throughput, coupling a current output of the inductor to a first port of a capacitor to charge the first port for a period equal to a pulse duration; and
at a time that the first port of the capacitor is charged to a clamping voltage, clamping the first port at the clamping voltage.
2. The method of claim 1 , where the clamping voltage is less than a surge voltage for the inductor and/or the capacitor, the surge voltage including a voltage at which surge protection circuitry interrupts a nominal operation to protect the inductor and/or the capacitor from damage.
3. The method of claim 2 , where the clamping voltage is less than 90% of the surge voltage for the inductor and/or the capacitor.
4. The method of claim 1 , where coupling the current output of the inductor to the first port of the capacitor includes operating a switch to couple the current output of the inductor to the first port of the capacitor.
5. The method of claim 1 , where current from the inductor during charging of the first port of the capacitor is constant such that a generated pulse has a flattened top, relative to rising and falling edges, for the period.
6. The method of claim 1 , further including preventing a reverse current flow from the capacitor to the inductor using a diode included in series between the inductor and the capacitor.
7. The method of claim 1 , further including discharging the inductor to a reset current after clamping the first port at the clamping voltage.
8. The method of claim 1 , where the pulse duration is selected based on a product of an inductance of the inductor to a capacitance of the capacitor.
9. The method of claim 1 , where the clamping is performed by a voltage clamp, including:
a Zener diode;
a gas ionization tube;
a metal-oxide varistor (MOV); and/or
a power converter configured to recover discharged energy from the inductor and/or the capacitor.
10. A device including:
an inductor;
a capacitor including a first port and a second port;
a switch configured to selectively couple, at a time that the inductor is charged to a selected current throughput, an output of the inductor to the first port of the capacitor to charge, for a period equal to a pulse duration, the first port to a clamping voltage and thereby generate a rising edge for a current pulse at the second port of the capacitor; and
a voltage clamp coupled to the first port, the voltage clamp configured to clamp, at a time that the first port is charged to the clamping voltage, the first port at the clamping voltage and thereby generate a falling edge for the current pulse.
11. The device of claim 10 , where the clamping voltage is less than a surge voltage for the inductor, the capacitor, and/or the switch, the surge voltage including a voltage at which surge protection circuitry interrupts nominal operation of the device to protect the inductor, the capacitor, and/or the switch from damage.
12. The device of claim 11 , where the surge voltage is selected based on a peak allowed current and characteristic impedance,
L
C
where L is an inductance of the inductor and C is the capacitance of the capacitor.
13. The device of claim 10 , where the switch includes a mechanical switch and/or a solid-state switch.
14. The device of claim 10 , further including a diode coupled in series between the inductor and the capacitor to prevent a reverse current flow from the capacitor to the inductor.
15. The device of claim 14 , where the voltage clamp is coupled in parallel to the switch between the inductor and the diode.
16. The device of claim 14 , where the voltage clamp is coupled in parallel to the switch between the diode and the first port of the capacitor.
17. The device of claim 10 , where the inductor is configured to provide a constant current during charging of the first port of the capacitor such that the current pulse has a flattened top, relative to rising and falling edges.
18. The method of claim 1 , where the voltage clamp, includes:
a Zener diode;
a gas ionization tube;
a metal-oxide varistor (MOV); and/or
a power converter configured to recover discharged energy from the inductor and/or the capacitor.
19. A device including:
an inductor;
a capacitor including:
a first port; and
a second port;
a switch to shape a first characteristic within current produced at the second port by selectively coupling an output of the inductor to the first port to charge the first port; and
a voltage clamp coupled to the first port, the voltage clamp configured to activate at a time the first port is charged to a clamping voltage by the inductor to shape a second characteristic within the current produced at the second port.
20. The device of claim 19 , where a pulse response time and a pulse duration are decoupled, the pulse response time and the pulse duration being associated with the first and second characteristics within the current produced at the second port.