Ultra low-noise true sub-volt band gap

摘要

A method and device are disclosed for providing an ultra low-noise hand gap voltage reference. The method detects a first voltage drop across a first diode reference, and a second voltage drop across a second voltage reference that includes a second diode. The first and second voltage drops are compared. Temperature compensation currents are supplied to the first diode reference and second voltage references in addition to constant currents, where the constant currents have the same value across a first temperature range. As a result of the constant current, a minimal amount of temperature compensation current is required. Alternatively stated, temperature compensation current is provided having a rate of change greater than PTAT. In response to comparing the first voltage drop to the second voltage drop, a true sub-volt hand gap voltage is supplied across a third voltage reference including a diode, that is constant across the first temperature range.

主权项

1. A band gap voltage reference device comprising:
a first operational amplifier (op amp) having a negative input connected to a first diode reference, a positive input connected to a second voltage reference including a second diode, and an output; a voltage compensation network having an input connected to the first op amp output, a first output to supply current to the first diode reference, a second output to supply current to the second voltage reference, and a third output connected to a third voltage reference including a third diode, to supply band gap current having a constant band gap reference voltage across a first temperature range; and, a constant current circuit having a first output connected between the voltage compensation network and the first diode reference to supply a first current that is constant across the first temperature range, and the constant current circuit having a second output connected between the voltage compensation network and the second voltage reference to supply a second current that is constant across the first temperature range, wherein the constant current circuit is uncompensated for temperature variations.