Transmitter Driver Circuit with Integrated Equalization
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Solution Overview
Problem
Conventional transmitters face challenges in increasing bandwidth and signal quality due to increased output capacitance caused by parallel connection of main and auxiliary drivers, which deteriorates signal quality.
Innovation Solution
A transmitter design where a PMOS transistor and an NMOS transistor are connected in series, with a driver control circuit adjusting gate voltages based on data signal levels and transitions to perform both signal driving and equalizing operations without an auxiliary driver, utilizing variable capacitors to control equalization voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an auxiliary driver is added in parallel with the main driver to perform pre-emphasis operation, then signal distortion is compensated, but output capacitance increases and bandwidth cannot be increased
Solution Approach 1:
The patent combines the main driver and auxiliary driver into a single integrated driver structure where the PMOS and NMOS transistors work together in parallel to perform both signal driving and pre-emphasis functions simultaneously, eliminating the need for separate auxiliary driver circuits that would increase output capacitance
Solution Approach 2:
The integrated driver performs multiple functions - it acts as both the main driver for signal output and the auxiliary driver for pre-emphasis operation, allowing a single circuit to accomplish what previously required separate components, thereby avoiding increased output capacitance
2Reliability
If an auxiliary driver is connected in parallel with the main driver, then pre-emphasis signal is provided, but output capacitance CIO increases
Solution Approach 1:
The patent merges the auxiliary driver functionality into the main driver circuit by using parallel-connected PMOS and NMOS transistors within the same driver block, so that pre-emphasis is achieved without adding separate auxiliary driver circuits that would increase output capacitance
Solution Approach 2:
The single driver circuit performs dual functions as both main driver and auxiliary driver, eliminating the need for additional parallel-connected driver circuits that would contribute to increased output capacitance at the output terminal
3Power
If output capacitance is increased by parallel connection of drivers, then more current is available, but bandwidth increases become difficult
Solution Approach 1:
The patent combines the driving functions of main and auxiliary drivers into a single integrated structure where PMOS and NMOS transistors work together, providing sufficient driving current through the integrated design without the need for multiple parallel-connected driver circuits that would increase output capacitance and limit bandwidth
Data Source
AI summary
A transmitter may include a driver having a PMOS transistor and an NMOS transistor connected in series between a first power supply and a second power supply. The driver may be configured to output an output signal. The transmitter may further include a driver control circuit configured to control a gate voltage of the PMOS transistor and a gate voltage of the NMOS transistor based on a level of a data signal, an occurrence of a level transition of the data signal, and a direction of the level transition of the data signal.