Differential Reference Voltage Buffer With Current Compensation
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Solution Overview
Problem
Traditional differential reference voltage buffers in integrated circuits face limitations in setting common mode voltage separately, leading to unequal output voltages and temperature-dependent performance, which affects accuracy and stability.
Innovation Solution
A differential reference voltage buffer circuit with a buffer stage, control circuit, current compensation circuit, and drive stage, where the control circuit includes operational amplifiers and resistors forming a negative feedback structure, and a current compensation circuit that adjusts for resistive load currents, allowing independent setting of common mode voltage and maintaining equal current ratios between buffer and drive stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the common mode voltage of the differential reference voltage is set separately, then the flexibility and adaptability of the buffer is improved, but the resistance feedback network generates current that flows into the buffer stage, causing the output voltages to become unequal and introducing bias voltage
Solution Approach 1:
The patent introduces a current compensation circuit as an intermediary component between the resistance feedback network and the buffer stage. This circuit actively compensates for the current generated by the resistance feedback network, preventing it from flowing into the buffer stage and disrupting the current ratio. The intermediary circuit thus enables independent common mode voltage setting while maintaining output voltage equality.
Solution Approach 2:
The patent employs feedback mechanisms where the current compensation circuit continuously monitors and adjusts the current distribution in the buffer stage. By using feedback control, the system maintains the correct current ratio between buffer and drive stages even when common mode voltage is set independently, thereby preventing bias voltage introduction.
2Measurement precision
If the current ratio between buffer stage and drive stage is maintained, then the output accuracy is improved, but the temperature dependence of the current-gate source voltage relationship causes offset voltage variation and performance degradation
Solution Approach 1:
The patent uses feedback control in the current compensation circuit to continuously monitor and adjust for temperature-induced variations in the current-gate source voltage relationship. This feedback mechanism compensates for offset voltage drift, maintaining output accuracy across different temperatures.
Solution Approach 2:
The patent compensates for temperature effects by dynamically adjusting circuit parameters through the current compensation circuit. As temperature changes affect the current-gate source voltage relationship, the compensation circuit modifies operating parameters to maintain stable offset voltage and consistent performance.
3Speed
If a traditional buffer structure with combined buffer and drive stages is used, then the circuit achieves speediness and low power consumption, but the common mode voltage cannot be set separately, limiting application flexibility
Solution Approach 1:
The patent segments the control functions by separating the common mode voltage setting from the differential signal path. The current compensation circuit handles common mode control independently while the traditional buffer-drive structure maintains differential signal processing, enabling both flexibility and speed.
Solution Approach 2:
The current compensation circuit acts as an intermediary that enables independent common mode voltage setting without interfering with the fast differential signal path. This intermediary structure adds flexibility while preserving the speed characteristics of the traditional buffer structure.
Data Source
AI summary
The present disclosure provides a differential reference voltage buffer, including: a buffer stage, including at least a first transistor and a second transistor; a control circuit, connected with the buffer stage and forming a negative feedback structure for generating a differential reference voltage; a current compensation circuit for compensating a resistive load current of the control circuit; and a drive stage for generating an output differential reference voltage. The differential reference voltage is generated according to an external input reference voltage and a common mode input voltage. The common mode voltage can be set separately, so that the flexibility is high. The current generated by a resistive network in the control circuit is compensated by the current compensation circuit, so that the current of a follow device in the buffer stage is not influenced by the control circuit, thereby generating a differential reference voltage with high accuracy output.