Programmable gain amplifier with colour balancing for CCD image sensors

The authors present a new programmable gain amplifier (PGA) with colour balancing for single-chip CCD colour image sensors. The PGA with synchronised gain switching allows higher SNR to be achieved in the amplified image while maintaining sufficient gain resolution and low power dissipation. A floating-point expression is used in the designed five-stage pipelined PGA for compact and low-power implementation. Low-noise gain switching with a cross-coupled ring counter sufficiently suppresses the pattern noise due to the high-speed gain switching. A prototype programmable gain amplifier with colour balancing has been implemented using 0.6 μm CMOS technology. The power consumption is 119 mW at 3.3 V supply voltage and 20 MHz pixel rate.