Low power buffer with dynamic gain control
The present disclosure provides a detailed description of techniques for implementing a low power buffer with dynamic gain control. More specifically, some embodiments of the present disclosure are directed to a buffer having a gain boost configuration and a current shunt circuit to control the gain of a respective gain boosting transistor of the gain boost configuration. The current shunt circuit and resulting gain are dynamically controlled by a gain control signal such that the buffer gain can be adjusted to within an acceptable range of the target gain for the current operating and device mismatch conditions. In one or more embodiments, the gain boost configuration with dynamic gain control can be deployed in a full differential implementation. Both analog and digital dynamic calibration and control techniques can be used to provide the gain control signals to multiple current shunt circuits and multiple buffers.
1. A communication system for communication over a receiver channel comprising:
a plurality of buffer circuits in the receiver channel, at least some of the plurality of buffer circuits electrically connected to a gain control signal; and
a DC gain control signal generation circuit comprising:
a DC signal generator that generates a bias current to set amplitudes of a pair of differential DC biasing signals;
a replica buffer having inputs that are electrically connected to the pair of differential DC biasing signals, the replica buffer to serve as a proxy for the plurality of buffer circuits in the receiver channel, and the replica buffer having at least one pair of differential DC output signals; and
a double difference amplifier that is electrically connected to the at least one pair of differential DC output signals and to the pair of differential DC biasing signals to produce the gain control signal that is electrically connected to at least some of the plurality of buffer circuits in the receiver channel.
2. The communication system of claim 1 , wherein the replica buffer in the DC gain control signal generation circuit exhibits a set of design characteristics that correspond to design characteristics of a respective buffer of the plurality of buffer circuits in the receiver channel.
3. The communication system of claim 1 , wherein a first intrinsic gain of the replica buffer in the DC gain control signal generation circuit and a second intrinsic gain of the respective buffer of the plurality of buffer circuits in the receiver channel are matched.
4. The communication system of claim 1 , wherein the replica buffer in the DC gain control signal generation circuit is physically located near at least one of the plurality of buffer circuits in the receiver channel.
5. The communication system of claim 1 wherein the replica buffer in the DC gain control signal generation circuit experiences a first set of operating conditions and at least one of the plurality of buffer circuits in the receiver channel experiences a matched set of operating conditions.