Programmable gain amplifier with controlled gain steps

摘要

Provided is a programmable gain amplifier that includes controlled gain steps that dynamically control an output voltage in real-time. The programmable gain amplifier includes a first transistor and a second transistor that includes respective control ports, input ports, and output ports. The programmable gain amplifier also includes a resistor connected to the output ports of the transistors. Further, at least a third transistor is connected to the output ports, in parallel with the resistor. On applying a control voltage to the third transistor and applying an input voltage to the first control port, the second control port is selectively modified by the control voltage to produce a desired output at the first input port and the second input port.

主权项

1. An apparatus, comprising:
a programmable gain amplifier, comprising:
a first transistor comprising a first control port, a first input port, and a first output port,a second transistor comprising a second control port, a second input port, and a second output port,a resistor comprising a first end connected to the first output port and a second end connected to the second output port, andat least a third transistor connected to the first output port and the second output port, in parallel with the resistor, wherein on applying a control voltage to the third transistor, and applying an input voltage to the first control port, the second control port is selectively modified by the control voltage to produce a specified output at the first input port and the second input pot; a replica programmable gain amplifier comprising a scaled version of the programmable gain amplifier, wherein the replica programmable gain amplifier produces an output voltage based on a direct current input voltage that is applied to an input of the replica programmable gain amplifier, and the direct current input voltage being determined as a function of a pre-determined delta voltage divided by a defined gain of the programmable gain amplifier; and a difference amplifier that is connected to the replica programmable gain amplifier and a voltage source, wherein the replica programmable gain amplifier provides the output voltage to a first input of the difference amplifier and the voltage source provides a pre-determined output voltage to a second input of the difference amplifier, the difference amplifier being configured to determine a value representative of a difference between the output voltage of the replica programmable gain amplifier and the pre-determined output voltage to produce the control voltage as an output of the difference amplifier.