Design On The PZT Driving Power Supply Based On ARM And DDS

DDS(Direct Digital Synthesis) is used widely on frequency synthesis technique. The controlling facility,fine frequency resolution,and high digital integration are the primary advantages of DDS,so it is easy for the design of the embedded system. There are some disadvantages of the PZT driving power supply based on traditional design,such as the uncontrollability by programming for phase and frequency,the lower digital integration level,the larger size and the higher power consumption.In order to solve these problems,ARM control system is used in the control circuit of this article and the wave of signal is,based on the Dustmen,the voltage of this signal is amplified by the high voltage operational amplifier circuit.The circuit of this power supply is divided into several modules,such as ARM control circuit,DDS system driving circuit and wave conditioning circuit,and the high voltage operational amplifier circuit.The micro-processor $3C2440 is used as the CPU in the control circuit,and the TFT touch screen is used as human-computer interface.AD9851 is chosen as the DDS chip,and its driving circuit,filter and conditioning circuit are designed.A kind of DDS and PLL unified method is used to solve the dispersion problem of the DDS.The high voltage operational amplifier circuit is designed as a two stage structure,which is based on voltage control mode. The core chip of the amplifier circuit is the high voltage operational amplifier PA92, and the compensating circuit is used to improve the bandwidth of the circuit.Over current protection circuit and fast discharge circuit are designed as the output of the power supply.The software of this power supply is based on the structure of WINCE.The programs and the configuration files of the DDS Stream Interface Driver are edited based on the structure of the WINCE driver.This Stream Interface Driver is integrated as a part of the WINCE software packages.By the main programs of the touch screen human-computer interface,the parameters of the wave set by the user are converted to the control words of the DDS chip.To renovate the output of the DDS chip,these control words are transformed to the DDS chip by the Stream Interface Driver,which is loaded by a dynamic loading method.There are some experiments about the power supply's output.In these experiments,the accuracy and frequency resolution of the signal wave generated by DDS,the accuracy and response characteristic of the dynamic output are also tested. These experiments show that,the wave of power supply's output has higher accuracy,and fine response characteristic to the vary of the frequency,so the power supply's characteristic can reach the requirement of the system.