All Starlight Xpress CCD cameras use Sony CCD chips with 'Hole accumulation diode' (HAD) pixel structures. The HAD design is completely different to that used in Kodak, Texas and SiTe devices etc. and generates a much lower dark current at any given chip temperature. This is because every pixel is covered by a very thin 'P' type silicon layer, which captures and removes thermally generated electrons from the surface of the pixel, where most thermal electrons originate. Because of this pixel structure, Sony CCDs have approximately 5 times less dark current than Kodak CCDs and up to 50 times less than non-MPP mode CCDs.
This inherently low dark signal means that extreme cooling is not necessary for good results and cameras can be built with smaller cooling fins and with lower power consumption for battery operation. To take advantage of these factors, Starlight Xpress cameras use single-stage Peltier coolers with only about 2 watts of power dissipation to the camera body. Large cooling fins and liquid cooling systems are quite unnecessary and are not used.
The Peltier device is operated from a constant-current switch-mode regulator in the power block, which gives a constant cooling rate with varying cable lengths and power supply voltages. The CCD temperature is not regulated, as any form of regulation sacrifices the ultimate temperature which can be reached and the inherently low dark current reduces the need for precise dark frame matching when calibrating your images. The actual CCD temperature is approximately -30 degrees C below ambient and is reached after only 10 minutes of operation, although the slow rise in body temperature will cause it to 'back off' by 2 or 3 degrees over the next 30 minutes.
Because of their Sony CCDs, Starlight Xpress cameras show less dark signal at a given temperature, than any other camera currently available to amateur astronomers. If you don't believe this, please ask your friends for sample dark frames from their non-Sony CCD cameras and compare!