Operational amplifier and start-up circuit of operational amplifier

A chip, wherein the chip comprises an operational amplifier comprising:

• a multi-stage amplifier;
• and
• a start-up circuit, comprising a first start-up transistor and a second start-up transistor, wherein a source of the first start-up transistor and a source of the second start-up transistor are connected to a tail bias node of a first-stage amplifier in the multi-stage amplifier, a gate of the first start-up transistor and a gate of the second start-up transistor are configured to connect to a first bias voltage, and a drain of the first start-up transistor and a drain of the second start-up transistor are connected to input terminals of a second or higher-stage amplifier.

An electronic device, wherein the electronic device comprises an operational amplifier comprising:

• a multi-stage amplifier;
• and
• a start-up circuit, comprising a first start-up transistor and a second start-up transistor, wherein a source of the first start-up transistor and a source of the second start-up transistor are connected to a tail bias node of a first-stage amplifier in the multi-stage amplifier, a gate of the first start-up transistor and a gate of the second start-up transistor are configured to connect to a first bias voltage, and a drain of the first start-up transistor and a drain of the second start-up transistor are connected to input terminals of a second or higher-stage amplifier.