Power consumption reduction in high current closed loop Hall Effect current sensors using Class D Amplifier

The closed loop hall effect current sensor is a popular current sensor because of its high bandwidth, ac and dc measurement, isolation. But the prime demerit of it is high power consumption at high currents. This is because of the losses in the linear power amplifier driving the compensating winding current. In this paper, a novel closed loop hall effect current sensor involving a Class D Amplifier as power amplifier is proposed to reduce the sensor power consumption and make the sensor more compact. This paper discusses the development of such a current sensor, it's stability issues, noise floor, procedures to overcome those problems, the tradeoff between noise and bandwidth. Finally a prototype current sensor is shown and it's performance is compared to a similar range commercially available current sensor. It is analysed and then verified experimentally that the proposed current sensor consumes much less power than the commercial sensor for higher currents.