Plural selectable RF oscillators for supplying capacitive loads

An oscillation circuit for applying, in response to an externally applied enable signal and an externally applied address signal, RF voltage across a selected one of a plurality of capacitive loads comprising,

• a plurality of oscillator stages each separately addressable according to said externally applied address signal when said external enable signal is applied, each oscillator stage including,
• a power driver circuit,
• a transformer having a primary and a secondary winding, said secondary winding being connected across the associated one of said capacitive loads,
• an enablement circuit coupled to said externally applied enable signal and address signal and providing to one of said power drivers selected in accordance with said applied address signal, an actuating signal for a predetermined period of time upon initiation of said enablement signal,
• a feedback circuit connected between each of said transformer primaries and said enablement circuit, said feedback circuit detecting negative going zero crossovers of the current waveform through any one of said transformer primaries and transmitting said detected zero crossover to said enablement circuit to maintain actuation of the selected power driver as long as said external enable signal is applied.

A quench/clamp circuit for providing half-cycle clamping across a transformer primary comprising,

• a first transistor coupled in series with a first diode across said transformer primary,
• a voltage supply,
• a second transistor coupled between said first transistor gate and one end of said transformer primary,
• a capacitor connected between the gate of said first transistor and the base of said second transistor,
• a resistor connected between said one end of said transformer primary and said second transistor base, thereby providing that alternating current through said transformer primary turns said second transistor on, discharging said capacitor and turning off said first transistor to prevent half-cycle clamping of current through said transformer primary, and that when alternating current is not provided through said transformer primary, said second transistor turns off, allowing said capacitor to charge and providing a unidirectional current path through said first diode and said first transistor to effect said half-cycle clamping.