Low-offset bandgap circuit and offset-cancelling circuit therein

摘要

A low-offset bandgap circuit including a core bandgap circuit and an offset-cancelling circuit is provided. The low-offset bandgap circuit provides a reference voltage at an output node. The core bandgap circuit includes a core operational amplifier to generate a core current. The offset-cancelling circuit is coupled to two input terminals of the core operational amplifier. The offset-cancelling circuit is configured to generate a compensation current according to the voltages at the two input terminals of the core operational amplifier so as to compensate for an offset voltage of the core operational amplifier. The reference voltage is generated according to the core current and the compensation current.

主权项

1. A low-offset bandgap circuit to provide a reference voltage at an output node, comprising:
a core bandgap circuit, comprising a core operational amplifier to generate a core current; and an offset-cancelling circuit, coupled to two input terminals of the core operational amplifier, and generating a compensation current according to voltages at the two input terminals of the core operational amplifier to compensate for an offset voltage of the core operational amplifier, wherein the reference voltage is generated according to the core current and the compensation current; wherein the offset-cancelling circuit comprises two operational amplifiers, and an offset voltage of each of the operational amplifiers is substantially equal to the offset voltage of the core operational amplifier.