Abstract: Problems associated with using bipolar differential circuits over a wide common mode voltage range are solved using first and second amplifier circuits 3 and 5, respectively operating over first and second voltage sub-ranges. The low voltage differential signal (LVDS) 1 is applied across a pair of series connected resistors 7 and 9, and to the inputs of the amplifiers 3 and 5. The common mode voltage signal 11 is fed to the inputs of third and fourth amplifiers 15 and 17. The third and fourth amplifiers 15 and 17 ensure that the LVDS receiver has a constant linear transfer characteristic over the differential input signal range and over the full common mode range, especially over the amplifier transition region.

Abstract: A photodiode detection circuit using a transimpedance amplifier circuit is disclosed. Overload current from the photodiode is diverted away from the amplifier to a voltage supply, e.g. ground, through an overload protection diode connected in series with the photodiode. A differential structure is also disclosed.

Abstract: There is disclosed a level shift circuit which has a differential input, for receiving input signals, and a differential output, for supplying output signals derived from the input signals. The level shift circuit further includes a control level setting input, and a feedback circuit for setting a common mode level of the output signals to a level set on the control level setting input. This allows the output common mode to be set accurately, independently of the input common mode.