Polarity switching circuit

Abstract

The invention relates to a polarity switching circuit. The polarity switching circuit comprises a first transistor switch, a second transistor switch, a third transistor switch, a fourth transistor switch, a first filtering circuit, a second filtering circuit, a third filtering circuit and a fourth filtering circuit. The first transistor switch and the fourth transistor switch are controlled by a first pulse width modulation signal. The second transistor switch and the third transistor switch are controlled by a second pulse width modulation signal. The second transistor switch and the fourth transistor switch are connected with a direct-current high voltage and are connected with the first transistor switch and the fourth transistor switch respectively. The first filtering circuit is connected with the first transistor switch, the second transistor switch and a contact of a piezoelectric actuator. The second filtering circuit is connected with the third transistor switch, the fourth transistor switch and the other contact of the piezoelectric actuator. When the first pulse width modulation signal and the second pulse width modulation signal alternately conduct switching between a high level and a low level, alternating-current voltage capable of generating a stable alternating-current waveform is promoted to be output and input into each contact of the piezoelectric actuator.

Description

technical field [0001] The invention relates to a polarity switching circuit, in particular to a polarity switching circuit capable of outputting an output AC voltage with a smooth AC waveform to drive a piezoelectric actuator. Background technique [0002] With the advancement of technology, various 3C products have been regarded as an important force to promote market growth. Undoubtedly, this development trend will continue, and with the advancement of microelectronics technology, 3C products not only have increasingly complex functions, but also tend to be smaller in size, and their portability has also been greatly improved. Therefore, it is convenient and easy to handle various affairs with 3C products. Recently, piezoelectric actuators have also been developed to be used in 3C products. Piezoelectric actuators have low voltage, no noise interference, small size, fast response, less heat generation, good precision, high conversion efficiency and Easy to control and m...

AI Technical Summary

Problems solved by technology

[0009] The main purpose of the present invention is to provide a polarity switching circuit to solve the problem that the conventional polarity switching circuit outputs an AC square wave to drive the piezoelectric actuator, resulting in large power loss and the piezoelectric actuator is in motion. In addition, because the known polarity switching circuit requires more transistor switches to form, the production cost of the conventional polarity switching circuit is increased, and the switching loss is also relatively large.

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