US Pat. No. 9,093,947

ZERO-VOLTAGE-SWITCHING (ZVS) PIEZOELECTRIC DRIVING CIRCUIT

MIDAS WEI TRADING CO., LT...

1. A zero-voltage-switching (ZVS) piezoelectric driving circuit, comprising:
a half-bridge driving circuit, used to receive an input DC voltage, and includes:
a high-side switch set and a low-side switch set connected in series, to convert said input DC voltage into an AC voltage
through switching of said high-side switch set and said low-side switch set;

a piezoelectric element, connected electrically to said half-bridge driving circuit, to receive said AC voltage, and drive
a load into action; and

at least a shunt circuit, connected electrically between said half-bridge driving circuit and said piezoelectric element,
said shunt circuit resonates with said half-bridge driving circuit, so that said high-side switch set and said low-side switch
set perform zero-voltage-switching (ZVS), wherein said high-side switch set includes a first parasitic capacitance, and said
low-side switch set includes a second parasitic capacitance, when said high-side switch set and said low-side switch set are
switched off, said shunt circuit is turned on, an input capacitor and said second parasitic capacitance of said piezoelectric
element discharge through said shunt circuit, while said first parasitic capacitance is charged, wherein said shunt circuit
includes a shunt inductor, a dual-direction switch, and a shunt power supply connected in series, when said shunt inductor,
said first parasitic capacitance, said second parasitic capacitance, and said input capacitor start to resonate, input AC
voltage of said piezoelectric element decrements to zero voltage, while voltage across said high-side switch set increments
to level of said input DC voltage.

US Pat. No. 11,071,190

ELECTROSTATIC DISCHARGE DEVICE

Midas Wei Trading Co., Lt...


1. An electrostatic discharge device comprising:at least two conductive materials, attached to an outer wall of an insulating hollow tube, separating from each other and overlapping in a radial direction of the insulating hollow tube, when liquid carrying static charges flows through and rubs against the insulating hollow tube, the static charges are accumulated on the insulating hollow tube to generate an electrostatic voltage across the at least two conductive materials; and
at least one electrostatic eliminating circuit, electrically connected to the at least two conductive materials and disconnected from a grounding terminal, receiving and eliminating the static charges through the at least two conductive materials to reduce the electrostatic voltage.