Reference Voltage Generation Circuit Merging Current Paths
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Solution Overview
Problem
Existing reference voltage generation circuits, such as those using band gap reference circuits, face issues with high power consumption and large chip area due to unnecessary current paths and fluctuations in output voltage caused by variations in process conditions and transistor threshold voltages, which are critical problems for reducing costs and power consumption in large-scale integrated circuits.
Innovation Solution
The proposed solution involves a reference voltage generation circuit design that includes a current mirror circuit and a resistive load circuit, where the current paths merge to reduce power consumption and output impedance, and the use of cascode current mirror structures and adjustable resistive elements to enhance precision and stability, thereby minimizing the dependency on voltage variations and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a third current path including a diode and resistive element is added to conduct a current being a multiple of those flowing through the first and second current paths, then the reference voltage can be generated with better temperature stability, but the power consumption increases and the chip area becomes larger
Solution Approach 1:
The patent merges the third current path with the first and second current paths by having them converge at a common node. The current mirror circuit causes the currents from all three paths to combine, allowing the reference voltage to be generated from the combined current while reducing the need for separate high-current paths. This merging reduces overall power consumption while maintaining the temperature stability benefits.
Solution Approach 2:
The current mirror circuit serves multiple functions simultaneously: it mirrors currents from the first and second paths, combines them with the third path current, and provides temperature compensation. By making the current mirror circuit multi-functional, the patent eliminates the need for additional dedicated circuits, thereby reducing power consumption and chip area while maintaining reference voltage stability.
2Stability of the object's composition
If a third current path including a diode and resistive element is added to conduct a current being a multiple of those flowing through the first and second current paths, then the reference voltage can be generated with better temperature stability, but the chip area becomes larger
Solution Approach 1:
The patent merges the third current path with the first and second current paths by having them converge at a common node. The current mirror circuit causes the currents from all three paths to combine, allowing the reference voltage to be generated from the combined current while reducing the need for separate high-current paths. This merging reduces overall power consumption while maintaining the temperature stability benefits.
Solution Approach 2:
The current mirror circuit serves multiple functions simultaneously: it mirrors currents from the first and second paths, combines them with the third path current, and provides temperature compensation. By making the current mirror circuit multi-functional, the patent eliminates the need for additional dedicated circuits, thereby reducing power consumption and chip area while maintaining reference voltage stability.
3Reliability
If the current ratio between the first and third current paths is shifted due to process condition variations in the PMOS transistor threshold voltage, then the circuit becomes more robust to process variations, but the output voltage precision deteriorates
Solution Approach 1:
The patent uses parameter changes in the transistor sizing ratios to compensate for process variations. By carefully selecting the width-to-length ratios of the MOS transistors in the current mirror circuit, the design achieves immunity to threshold voltage variations. The specific parameter relationships (such as W/L ratios) are chosen to cancel out the effects of process variations, thereby maintaining both robustness and precision simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design achieves a precise, stable reference voltage with reduced current consumption and chip area, effectively addressing the challenges of power efficiency and cost reduction in integrated circuits.
Implementation Method 1
A reference voltage generation circuit including a band gap reference circuit (referred also as a BGR circuit) is typically used in various analog circuits provided in semiconductor devices in order to suppress variations in the overall characteristics of the circuits due to variations in the power supply voltage and the temperature
Data Source
AI summary
A reference voltage generation circuit of the present invention includes: a band gap reference-type current generation circuit for controlling each of currents flowing through a first current path and a second current path, which are extending from a first node to a second node, to be a predetermined reference current, by utilizing a voltage difference occurring between a pair of transistors or diodes; and a resistive load circuit provided between the second node and a third node.