Patent ID: 7944283

Claim:
A reference current bias circuit, comprising: a self-bias circuit configured to provide a bias current to an amplifier; a basic bandgap circuit coupled to inputs of the amplifier; a startup circuit configured to support an initial operation of the amplifier; a temperature compensator configured to include a first mirroring unit for mirroring current according to a positive temperature coefficient characteristic from the basic bandgap circuit; and a second mirroring unit for mirroring current according to a negative temperature coefficient characteristic from the basic bandgap circuit, and to provide a reference current by combining the current of the first mirroring unit and the current of the second mirroring unit; and a reference current mirroring unit configured to generate reference current biases based on the reference current from the temperature compensator, wherein the second mirroring unit includes: an NMOS transistor with long channel length configured to have a source coupled to the ground through a first resistor, a gate connected to the P-node of a PN-junction element of a basic bandgap circuit and a drain connected to a current mirror; and the current mirror configured to mirror a current flowing through the first resistor connected to the output of the first mirroring unit and to the input of the reference current mirroring unit through a second resistor, wherein the current mirror comprises two PMOS transitors and has the area ratio of N:1 to control the mirroring current for the temperature compensation between the positive temperature coefficient and the negative temperature coefficient and to have a low power consumption and small layout area of the first resistor.