Design of Programmable DC Electronic Load

Owning to the current or voltage can be artificially controlled, programmable DC electronic load plays an essential role in current and future power source testing. In this paper, we propose an electronic load which is easy to operate. The core of the design is power control module, where the compared result of current or voltage is used to control the current through the NMOS power transistor IRF540 or the voltage between the two ports of the electronic load. The keyboard and LCD based on MSP430 provide a friendly man-machine interactive interface. By establishing a feedback network using an operational amplifier, it can maintain the stability of the current or the voltage. The voltage follower and the differential amplifiers are utilized to sample the voltage and current signal. Moreover, overcurrent protection function is integrated in this design to enhance the robustness.