A Key Techonology Of Power Driven For Synchronous Scan Steak Camera

Synchronous scan streak cameras use the quasi linear part of sine signals to scan the input photoelectrons repeatedly when it works in synchronous modeand so that the weak signal is accumulated strong enough to be detected.The quasi linear part of the sine signal should be strictly synchronous to the input light impulse in the whole process,because this can enhance sensitivity and improve the dynamic measurement range.Our lab uses a new method with PLL and DDS to generate a high frequency scan signal.This technology can achieve synchronous scanning signal and the incident light of the strict synchronization and timing jitter is less than 5ps.But the signal generated by this method is too weak to generate a sufficiently high voltage on the rear-level scanning deflection plate.This signal could not achieve the successful deflection of the incident photoelectron.This paper uses a power driving method based on LDMOS radio frequency amplification technology.It combines the advantages of the differential amplifier and the LDMOS high power RF amplifier.The differential amplifier is mainly used for noise suppression and the LDMOS device can achieve the important high power output.This combination achieves the power amplification of the signal from the first stage.After a introduction of researches on streak cameras,the article introduces working principles and advantages of differential amplifier circuits and LDMOS high power devices.It provides theoretical basis for this power driving system.Then the three-stage amplifier system based on LDMOS high power devices is introduced.The circuit composition and design principles of each part of the three-stage amplifier are introduced in detail and the design of the peripheral circuit is introduced.Experiment results show that when the system works under the frequency of 80 MHz to 120 MHz,time jitter is 6.7ps and amplification factor is 49.6dB.The 324 V driving voltage is obtained on the deflection plate.The power circuit designed in this paper is of great significance to improve the scanning performance of the streak camera.