Low-voltage CMOS error amplifier with implicit reference

An analog error amplifier, comprising:

• an amplifier circuit including an input signal input, a bias signal input, an output signal output, a basic amplifier connected to the input signal input to receive an input signal and to the output signal output, wherein the basic amplifier produces an output signal on the output signal output in response to the input signal on the input signal input, and wherein a reference threshold of the basic amplifier is responsive to a bias signal on the bias signal input, such that the output signal represents a difference between the input signal and the bias signal;
• a replica bias circuit including a reference signal input, a bias signal output, a plurality of amplifier stages connected in series between the reference signal input and the bias signal output, and wherein the bias signal output is connected in a feedback loop to the plurality of amplifier stages, such that the replica bias circuit produces a bias signal on the bias signal output in response to a reference signal on the reference signal input and drives the bias signal to be equal to the reference signal;
• and
• wherein the bias signal output of the replica bias circuit is connected to the bias signal input of the amplifier circuit such that the amplifier circuit and the replica bias circuit together produce the output signal in response to the input signal and the reference signal such that the output signal represents a difference between the input signal and the reference signal.

An analog error amplifier, comprising:

• a plurality of amplifier circuits, wherein each of the plurality of amplifier circuits includes an input signal input, a bias signal input, and an output signal output, and wherein the amplifier circuit produces an output signal on the output signal output in response to an input signal on the input signal input and a bias signal on the bias signal input such that the output signal represents a difference between the input signal and the bias signal;
• and
• a single replica bias circuit including a reference signal input and a bias signal output, wherein the replica bias circuit produces a bias signal on the bias signal output in response to a reference signal on the reference signal input and drives the bias signal to be equal to the reference signal;
• and
• wherein the bias signal output of the single replica bias circuit is connected to the bias signal input of each of the plurality of amplifier circuits, such that each of the plurality of amplifier circuits produces an output signal in response to the input signal to the amplifier circuit and the reference signal to the single replica bias circuit such that the output signal represents a difference between the input signal and the reference signal.