This paper reports an improved Current Mirroring Integration (CMI) unit cell and a new readout structure based on it. The new structure combines the benefits of the current mirroring direct injection and switch current integration structures, satisfying the requirements for the high resolution and high performance IR FPA readouts. The improved CMI readout circuit provides very high injection efficiency, almost-zero detector bias, and large dynamic range, while it can be implemented in a small pixel area. the circuit provides a maximum charge storage capacity of 5.25 X 107 electrons and a maximum transimpedence of 6 X 107 (Omega) for a 5V power supply and a 2pF integration capacitance, which is paled outside the unit cell. The unit cell employs only nine MOS transistors and occupies an area of 20micrometers X 25 micrometers in a 0.8 micrometers CMOS process.