Patent ID: 6842078

Claim:
A ring oscillator circuit device comprising: an odd number of inverting stages wherein each said inverting stage has an input terminal and an output terminal and wherein said inverter stages are coupled in a ring such that said output terminals of preceding said inverting stages are coupled to said input terminals of subsequent said inverting stages wherein one of said inverting stages comprises a logic gate having an additional input terminal that is coupled to an enable signal; a plurality of first variable capacitors wherein each said output terminal of each said inverting stage is coupled to one of said first variable capacitors and wherein all said first variable capacitor bulk semiconductor regions are coupled to a first bulk voltage; and a plurality of second variable capacitors wherein each said output terminal of each said inverting stage is coupled to one of said second variable capacitors and wherein all said second variable capacitor bulk semiconductor regions are coupled to a second bulk voltage wherein said enable signal, said first bulk voltage, and said second bulk voltage are accessible for probe testing via pad structures.