INTEGRATED CIRCUIT OF A CONSTANT REFERENCE VOLTAGE GENERATOR WITH SUB-1 V SUPPLY VOLTAGE

摘要

An integrated circuit of a reference voltage generator, designed so that it is used as a bias circuit of low sub-1V supply. The proposed reference voltage circuit consists of a common core of a conventional bandgap reference circuit, based on the use of a substrate vertical p-n-p bipolar transistors, and a voltage-to-current converter, V-I. The common core provides a current with positive temperature coefficient, while the voltage-current converter converts the emitter-base voltage of the substrate vertical p-n-p bipolar transistor of the common core to a current with negative temperature coefficient. These two currents with opposite temperature coefficients are suitably summed so that a total output current independent from the temperature variations is obtained. The output current is linearly converted to output reference voltage via a resistor. Two operational amplifiers are used with an output stage of the rail-to-rail type, so that the operation of the circuit is robust. The proposed invention can provide a current proportional to the absolute temperature, PTAT.