Differential Driver Circuit for Stable Amplitude and Common Voltage
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Solution Overview
Problem
Conventional drive circuits experience variations in amplitude and common voltage of output signals due to input offset of operational amplifiers in voltage regulators, degrading signal quality.
Innovation Solution
A drive circuit with a driver, amplitude adjuster, and common voltage adjuster that generates and adjusts voltages using a pair of voltages, including a common-side reference voltage generator and intermediate voltage generator, to stabilize amplitude and common voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage regulators are disposed on both power supply side and ground side to improve PSRR, then power supply rejection ratio is improved, but variations in amplitude and common voltage occur due to operational amplifier input offset
Solution Approach 1:
The patent extracts the ground side voltage regulator from the system, keeping only the power supply side voltage regulator. This eliminates the source of offset-induced variations while maintaining PSRR improvement through the remaining power supply side regulation
Solution Approach 2:
The patent transitions from a symmetric dual-sided voltage regulation architecture to an asymmetric single-sided regulation architecture. Only the power supply side maintains voltage regulation functionality, while the ground side directly provides the reference potential, creating an asymmetric structure that eliminates offset cancellation issues
2Reliability
If dual voltage regulators are used to control driver amplitude, then power supply rejection ratio is improved, but signal quality degrades due to offset variations
Solution Approach 1:
The ground side voltage regulator is extracted and removed from the system. The power supply side voltage regulator remains to maintain PSRR, while the ground side directly provides stable reference potential, eliminating the offset-induced signal quality degradation
Solution Approach 2:
The power supply voltage serves as an intermediary element. The power supply side voltage regulator controls the power supply voltage to indirectly control the driver output amplitude, eliminating the need for direct ground side regulation and its associated offset problems
Data Source
AI summary
In a drive circuit provided with a driver, signal quality is improved.There is provided a drive circuit that includes a driver, an amplitude adjuster, and a common voltage adjuster. In this drive circuit, the driver outputs a differential signal. The amplitude adjuster generates, from one of a pair of voltages, the other of the pair of voltages, and supplies the other of the pair of voltages to one of a power supply terminal and a ground terminal of the driver. The common voltage adjuster generates the one of the pair of voltages from an intermediate voltage between the pair of voltages, and supplies the one of the pair of voltages to the other of the power supply terminal and the ground terminal.