High Efficiency Low Voltage Ripple Piezoelectric Ceramics Driver

Using the inverse piezoelectric effect, piezoelectric ceramic actuators can implement the micro-displacement under external electric field. With the development of micro-displacement technology, its applications prosper in many areas of human life, such as inkjet printer, bio-cell sensor, precision machine, micro-surgery and so on. With the advantage of high load capability, high resolution, low noise, fast frequency response and high anti-disturbance characteristics, the piezoelectric ceramic actuator becomes a perfect choice for micro-displacement actuators. Recently, proven the high efficiency of the piezoelectric ceramics driving power, some applications such as ultra-precision micro-displacement applications also require low output voltage ripple. Thus, it is important to develop a high efficiency and low ripple piezoelectric ceramics power supply.In some applications where the output voltage is required to be gradient, compared to traditional piezoelectric ceramic actuator power supply, the new piezoelectric ceramic actuator power supply with a current limiting resistor has lower power consumption of main power switches, which results to a smaller heat sink and reduction of the power supply volume. This paper analyses the principle of linear amplifier of piezoelectric ceramic, and derives its main expressions of the power devices loss. Compared to traditional linear amplifier, the new power supply performs a lower power loss.Considering the MOSFETs of linear amplifier work in linear mode, and the amplifier cannot recycle the passive energy stored in capacitive load, the high turn-on loss will cause serious heating problem. This paper analyzes the power supply with its MOSFETs working in switch mode, which shows that the turn-on loss is very low and the passive energy is recycled, so power supply with its MOSFETs working in switch mode has higher efficiency.The linear amplifier has good output regulation but suffers from serious heating problem, while switching amplifier has high efficiency but sacrifices the output ripple. This paper proposed a hybrid power supply, which combines the advantages of the two kinds mentioned above. The theoretical analysis and experimental results show that hybrid power supply improves the operation efficiency and reduces the output ripple simultaneously.