Method and system for generating a low voltage reference

摘要

A single cell voltage reference operates under low power supply requirements to provide a configurable voltage reference. The single cell voltage reference includes a diode device that is biased as a voltage source. Two series connected resistive devices are connected in parallel with the diode device. The diode is biased with a current that is proportional to delta Vbe/R, such that the impedance of the diode tracks R. Another current source that is also proportional to delta Vbe/R is provided at the junction of the two resistors such that the voltage across one of the two resistors may be employed as a reference voltage that is less than 1.2V. The ratio of the resistors and scales the reference voltage level. Voltages that are below 1.2V are provided that are temperature compensated similar to a band-gap reference. The diode voltage as driven by a current source determines the lower limit of the reference voltage. The reference voltage may be combined with a buffer or an operational amplifier such that a regulated supply can be provided that is below 1.2V. Metal masks may be arranged to permit reconfiguration of the voltage reference cell for use above 1.2V, or to change the regulation voltage without redesigning the voltage reference cell.