Variable level shifter and multiplier suitable for low-voltage differential operation

摘要

A variable level shifter has a first transconductor cell receiving a first pair of voltages, and second and third transconductor cells both receiving a second pair of voltages. The transconductor cells are differential voltage-to-current amplifiers employing field-effect transistors. The two current outputs of the first transconductor cell are coupled to respective output terminals. One current output of the second transconductor cell is coupled to one of these output terminals, and the corresponding current output of the third transconductor cell is coupled to the other output terminal. A fourth transconductor cell may be added to obtain two pairs of outputs shifted in opposite directions. A differential multiplier can be constructed using this four-cell variable level shifter and additional field-effect transistors.