Patent ID: 7026765

Claim:
An energy recovery apparatus, comprising: a sustaining voltage source for applying a sustaining voltage to a first electrode and a second electrode formed on an upper substrate; an equivalent capacitive load formed between the first electrode and the second electrode; a power source capacitor disposed between the sustaining voltage source and a ground; a first switch and a third switch formed between the sustaining voltage source and the ground in parallel to the power source capacitor; a second switch and a fourth switch formed between the sustaining voltage source and the ground in parallel to the first and third switches; and an inductor with a first end connected to the first and third switches and a second end-coupled to the second and fourth switches; and wherein the fourth switch is turned on in a first and second time period and the first switch is turned on in the second time period so a voltage charged in the power source capacitor causes a current to be applied to the inductor, the first and fourth switches are turned off in a third and fourth time period such that the current applied to the inductor is applied to the equivalent capacitive load, the third switch is turned on in a fifth time period so a voltage charged in the equivalent capacitive load causes a current to be applied to the inductor, and the third switch is turned off and the fourth switch is turned on in a time period following the fifth time period such that the current applied to the inductor is applied to the power source capacitor.