Digital to analog and analog to digital converters with bipolar output signals

摘要

A digital to analog converter (100) utilizes a current mirror connected to a reference voltage (VREF) to generate a constant reference current (IREF). A voltage divider (R1 and R2) is used in conjunction with a plurality of MOS transistors (X1-XN) serving as current mirrors having specific current carrying capabilities which are controlled by selected binary digits (bits) of a digital signal. By the appropriate connection of desired ones of said plurality of MOS transistors, a specific fraction of said reference current is caused to flow through said plurality of MOS transistors. The amount of current flowing through said plurality of MOS transistors generates an output voltage (VOUT) from the digital to analog converter of this invention. This output voltage may be positive or negative with respect to the reference voltage, thus the output voltage is bipolar.