Bridge Voltage Reference Circuit for Threshold Variation Compensation
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Solution Overview
Problem
Existing voltage reference circuits are sensitive to variations in transistor parameters, such as manufacturing dispersions and temperature, leading to instability in the reference voltage.
Innovation Solution
A voltage reference circuit is designed with a specific configuration of depletion-mode and enhancement-mode transistors, along with dipoles, to compensate for variations in transistor threshold values, thereby stabilizing the reference voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional voltage reference circuits use depletion-mode and enhancement-mode transistors in series configuration, then low current consumption is achieved (less than 1 μA), but the reference voltage stability deteriorates due to sensitivity to transistor parameter variations
Solution Approach 1:
The patent changes the circuit topology from a simple series configuration to a bridge configuration with four arms. This structural parameter change allows the circuit to achieve both low current consumption and high stability by enabling differential measurement and compensation of transistor parameter variations through the balanced bridge structure.
Solution Approach 2:
The patent implements feedback mechanisms where the output voltage is fed back to control the transistor gates, creating a self-regulating system. This feedback compensates for parameter variations in real-time, maintaining reference voltage stability while operating at low current levels.
2Reliability
If the number of depletion-mode transistors is increased to compensate for threshold value variations, then reference voltage stability improves, but device complexity increases
Solution Approach 1:
The patent segments the voltage reference function into four separate transistor arms arranged in a bridge configuration. Each arm contributes to the overall stability through its specific transistor parameter variations, and the segmented structure allows independent optimization and compensation of each arm, achieving high stability without excessive complexity.
Solution Approach 2:
The patent employs asymmetric transistor pairing where depletion-mode and enhancement-mode transistors are strategically placed in different arms of the bridge. This asymmetric arrangement exploits the complementary threshold voltage characteristics of the two transistor types to cancel out parameter variations, improving stability without requiring symmetric increases in component count.
Data Source
AI summary
The invention relates to a voltage reference circuit comprising: a trailing transistor, the source and the gate of which are connected to the terminals of the dipole, a connecting quadrupole, the first terminal of which is connected to the gate of a leading transistor, the second terminal is connected to the source of the leading transistor, the third terminal to the source of the trailing transistor and the fourth terminal to the drain of the trailing transistor, the reference voltage being supplied to the source of the leading transistor, and a base transistor, the source of which is connected to the ground and the gate of which is connected to its drain, said drain being connected to a terminal of a second dipole, the other terminal of which is connected to the first dipole.