Patent ID: 7209782

Claim:
An electrotherapy unit comprising: a digital force modutator; a power supply connected to the digital force modutator and supplying power to the digital force modutator; a central processor connected to the digital force modutator, the central processor being downloadable with programs to output signals for controlling operation of the digital force modutator; a voltage-increasing transformer including a primary coil and a secondary coil; and two conductive pads connected to the secondary coil; the digital force modutator comprising two pairs of transistors, each said transistor including an input side connected to the central processor, the central processor controlling conduction/non-conduction of the transistors, a loop for each said transistor being connected to the power supply and the primary coil of the voltage-increasing transformer, a diode and a capacitor being connected in parallel between a collector and an emitter of each said transistor; wherein the voltage-increasing transformer, one of the transistor, one of the diodes connected to said one of the transistors, and one of the capacitors connected to said one of the transistors together form a loop for providing a near-zero voltage switching function.