Digitally controlled multi-phase electronic current sink

In this paper, a digital-controlled multi-phase electronic current sink is proposed. The wide Safe Operation Area (SOA) MOSFETs are used as the power dissipating device, which are regulated to the saturation region by filtered PWM gate signals. Due to the inherent limitation of switching frequency and sampling rate in digital systems, interleaved multi-phase PWM scheme is proposed to provide active current ripple mitigation. The power stage and signal conditioning peripherals are designed and modeled; the digital controller is implemented to provide regulation for constant current and pulsed current sink modes. The digital signal controller dsPIC33FJ64GS606 is used to provide four-phase interleaved high-precision PWM and real time control for the prototype. The experimental test results indicate that the proposed system performs well in the steady-state and dynamic testing, and is applicable to future digitalized testing equipments.