A novel current sensing technique for photovoltaic MPPT applications

Abstract

In this paper an improved current sensing technique suitable for DC-DC Boost converter is proposed. Its principle of operation is based on exploiting the DC resistance (RDCR) of the input inductor L to detect the input current by sensing the voltage drop across it. A highly linear differential Gm-transconductor and a V-I converter along with a current integrator are utilized to further process this voltage drop and produce a square-wave pulse signal with its frequency proportional to the input current. The current sensor circuit has been designed and fabricated in 180nm XFAB technology and simulation results over PVT corners exhibits a frequency operation range 3kHz-90kHz and worst-case frequency linearity error of 6.4%.