Design Of High-voltage Power Supply For Capillary Electrophoresis Based On ARM

As an effective way of micro flow separation and analysis, microchip capillary electropho--resis has been widely used in biochemical measurement, protein separation, medical research and so on. In the detection of microchip capillary electrophoresis, high voltage must be applied in the reservoirs of electrophoresis chip, and the sample injection and separation can be achieved through electrode switch, so high-voltage power system for capillary electrophoresis has played an important role in the analysis of microchip capillary electrophoresis. Original high voltage dc power supplies are unstable in output, large, and can only accomplish the detection of single-chip electrophoresis, so this paper carries out the design of high holtage power supply for capillary electrophoresis based on ARM.A high voltage power system for capillary electrophoresis made use of three high voltage modules was designed whose core was STM32F103. With close-loop feedback controlling output of high voltage, the stability of output had improved. Relay array controlled electrodes switching, which satisfied voltage switch of single-chip and multi-chip electrophoresis detection, shortening the switching time and improving detection precision and greatly reducing the man-made factors. The injection voltage, separation voltage, injection time and separation time could be set through keyboard, LCD could not only show parameter setting, but also monitor current detecting state, and the system had short-circuit protection function. Designing a upper computer software based on Visual C++, the analysis of system parameters were realized with MFC graphics drawing function. This system could realize three high voltage continuous and adjustable voltage output with from 0 to 5V controlling from 0 to 5000V, relative error of output voltage was less than 0.3%, and maximum output current was 0.25mA.Through the tests of high power output, time-drift, the relation of load and output voltage and electrode switching time, the results proved that the system had met the design requirements. The system was applied to single-channel and multi-channel capillary electrophoresis injection and separation detection with Rhodamine B, and obtained ideal results. It showed that this system had advantages of small size, high degree of automation, steady output and could completely satisfy the need of capillary electrophoresis analysis.