Low-voltage band-gap voltage reference circuit

摘要

The present application discusses low voltage band-gap voltage reference circuit and methods. In an example the circuit can include a current mirror, an operational amplifier adopting an N-Metal-Oxide-Semiconductor (NMOS) input pair structure, a band-gap output circuit, an adaptive adjustment circuit; and two branches of Bipolar Junction Transistor (BJT). The current mirror can be configured to receive an output signal of the operational amplifier and to provide a current to the two branches of BJT. The operational amplifier can be configured to differentially input voltages at the upper ends of the two branches of BJT, to generate the output signal to the current mirror, and to equalize the voltages at the upper ends of the two branches of BJT using a deep negative feedback.

主权项

1. A low-voltage band-gap voltage reference circuit, comprising:
a current mirror; an operational amplifier adopting an N-Metal-Oxide-Semiconductor (NMOS) input pair structure; a bandgap output circuit; an adaptive adjustment circuit; two branches of Bipolar Junction Transistor (BJT), and a resistor network; wherein the current mirror is configured to receive an output signal of the operational amplifier and to provide a current to the two branches of BJT; wherein the operational amplifier is configured to differentially input voltages at the upper ends of the two branches of BJT, to generate the output signal to the current mirror, and to equalize the voltages at the upper ends of the two branches of BJT using a deep negative feedback; wherein the adaptive adjustment circuit is configured to adaptively adjust a base voltage of common base BJTs in the two branches of BJT according to an operating condition of an NMOS input pair in the operational amplifier; wherein the two branches of BJT are configured to control respective current of the two branches of BJT according to the base voltage of the common base BJTs to ensure normal operation of the operational amplifier; wherein a first branch of the two branches of BJT include a first resistor, wherein the resistor network includes:
a second resistor,a third resistor, anda fourth resistor,wherein the second and third resistor are coupled in series between the upper ends of the two branches of BJT,wherein the fourth resistor is coupled between a first node common to both the second and third resistors and a second node providing the base voltage of the common base BJTs in the two branches of BJT; wherein the band-gap output circuit is configured to generate an output voltage of the low-voltage band-gap voltage reference circuit by mirroring; and wherein the output voltage of the low-voltage band-gap voltage reference circuit can be adjusted using a ratio of the first resistor and the fourth resistor.