Integrated current sensor for automotive power switches

An original and modern integrated current sensor is designed and presented in this paper. It can provide a sense current proportional to an output current available to the microcontroller via an external resistor. The ratio between output and sense current is modeled and simulated. The errors between the two currents increase in low currents domain. A solution consisting in a gate back regulation circuit is proposed in order to minimize the low currents errors. The output current sensing, the amplifier and the gate back regulation circuit topologies are described in the paper. Comparative studies between the analytical model and the simulation results were performed.