Amplifier with adaptive biasing
AssigneeTexas Instruments Incorporated
InventorBradford Lawrence Hunter
Life of this patent
Estimating the term…
Abstract
An amplifier circuit includes an amplifier, a resistor, and an adaptive bias circuit. The amplifier includes an output and a tail input. The amplifier is configured to generate an output signal representative of a difference of a first input signal and a second input signal. The resistor is coupled to the output of the amplifier. The resistor is configured to lower an output resistance of the amplifier. The adaptive bias circuit is coupled between the output of the amplifier and the tail input of the amplifier. The adaptive bias circuit is configured to generate a detection current based on the output signal, and provide the detection current to the tail input of the amplifier to increase the gain of the amplifier based on the output signal.
Claims17
An amplifier circuit, comprising:
- an amplifier having an amplifier input, a tail current input, and an amplifier output;
- a resistor having first and second terminals, the second terminal coupled to the amplifier output;
- an adaptive bias circuit including:
- a detector circuit having a detector input and a detector output, wherein the detector input is coupled to the amplifier output;
- a current mirror circuit having a current mirror input and a current mirror output, wherein the current mirror input is coupled to the detector output;
- and
- a transistor having first and second current terminals and a first control terminal, wherein the first current terminal is coupled to a power supply terminal, the second current terminal is coupled to the first terminal of the resistor, and the first control terminal is coupled to the second current terminal.
An amplifier circuit, comprising:
- an amplifier having an amplifier input, a tail current input, and an amplifier output, and capable of generating an output signal at the amplifier output that is representative of a difference of a first input signal and a second input signal;
- a resistor coupled to the amplifier output, and capable of lowering an output resistance of the amplifier;
- an adaptive bias circuit coupled between the amplifier output and the tail current input, and capable of providing to the tail current input a detection current responsive to the output signal, wherein a gain of the amplifier is increased in response to the output signal;
- and
- a diode-connected transistor capable of passing a current to the amplifier output through the resistor.
A voltage regulator circuit, comprising:
- an amplifier having an amplifier input, a tail current input, and an amplifier output, and capable of generating an error signal representative of a difference between an output voltage and a reference voltage;
- a load resistor coupled to the amplifier output, and capable of lowering an output resistance of the amplifier;
- an adaptive bias circuit coupled between the amplifier output and the tail current input, and capable of:
- generating a detection current based on the error signal;
- and
- providing the detection current to the tail current input to increase a gain of the amplifier in response to the error signal;
- and
- a field effect transistor (FET) coupled to the amplifier output, and capable of passing a current in response to the error signal.
A voltage regulator circuit including:
- an amplifier having an amplifier input, a tail current input, and an amplifier output, and capable of generating an output signal at the amplifier output that is representative of a difference of a first input signal and a second input signal;
- a resistor coupled to the amplifier output, and capable of lowering an output resistance of the amplifier;
- an adaptive bias circuit coupled between the amplifier output and the tail current input, and capable of providing to the tail current input a detection current responsive to the output signal, wherein a gain of the amplifier is increased in response to the output signal;
- and
- a diode-connected transistor capable of passing a current to the amplifier output through the resistor;
- and
- an output stage coupled to the amplifier output.
Dependencies are inferred from the claim text.