76results about How to "Reduce the voltage amplitude" patented technology

The invention provides a driving method used for an ultrasonic motor. As for the ultrasonic motor with piezoelectric elements with the number of four or the multiple of four, when the piezoelectric elements are provided with common-ground structures, adjacent piezoelectric elements use a polarization type of ++__; the voltage increment of a three-phase bridge-typed inverter circuit is controlled so as to gain two-phase orthogonal AC voltages and to supply the power for all piezoelectric elements sequentially, thus effectively reducing the voltage amplitude of the power supply, reducing the number of the switching transistor and improving the efficiency of the driving circuit. As for the ultrasonic motor, a type of two single-polarity DC pulse voltage power supplies with the electric angle difference of 90 degrees can be used to replace the normal AC output, thus greatly improving the switching frequency of the transistor and facilitating the miniaturization and integration of the driving circuit. As for the ultrasonic motor with piezoelectric elements with the number of three or the multiple of three, voltage increment of a three-phase bridge-typed inverter circuit is controlled so as to gain three-phase symmetric AC voltages and to supply the power for all piezoelectric elements sequentially, thus effectively reducing the number of the switching transistor and improving the efficiency of the driving circuit.

The present invention relates to compound semiconductor ESD protection devices of three types. The device comprises a multi-gate enhancement mode PET (E-PET). For the type I compound semiconductor ESD protection device, the source electrode is connected to the plural gate electrodes through at least one first resistor, and the drain electrode is connected to the plural gate electrodes through at least one second resistor. For the type II compound semiconductor ESD protection device, at least one of the plural gate electrodes are connected to at least one of the inter-gate regions between two adjacent gate electrodes through at least one fourth resistor. For the type compound semiconductor ESD protection device, the plural gate electrodes are connected to the source or drain electrodes through at least one seventh resistor. Any two gate electrodes in the three types of compound semiconductor ESD protection devices can be connected by a resistor.

The present invention relates to a method, of providing adaptive impedance in a Power Amplifier (PA), by providing more than one transistors in which one transistor is used to change the load line or to linearize the input signal by adapting the biasing of each transistor, wherein the transistors are connected in parallel.