Bandgap Reference Voltage Circuit Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bandgap reference voltage generating circuits face instability due to variations in system voltage and temperature, affecting the accuracy and reliability of the reference voltage in portable electronic devices.
Innovation Solution
A bandgap reference voltage generating circuit comprising a four-terminal current source circuit, a regulator circuit, and a temperature-compensating circuit, which maintains a steady reference voltage independent of system voltage and temperature variations by using depletion mode transistors and carefully designed resistor networks to compensate temperature curves from second-order to third-order.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional bandgap reference voltage source circuit is used, then the reference voltage can be generated based on Vbe and ΔVbe, but the reference voltage becomes unstable when ambient temperature or system voltage varies
Solution Approach 1:
The circuit is divided into functionally independent modules: a four-terminal current source circuit for voltage generation, a regulator circuit for voltage stabilization, and a temperature-compensating circuit for temperature correction. This segmentation allows each module to be optimized independently, with the current source generating voltages independent of system voltage variations and the temperature-compensating circuit specifically addressing temperature drift, thereby achieving stable reference voltage output under varying conditions.
Solution Approach 2:
The patent employs parameter changes by using depletion mode transistors with specific threshold voltage characteristics and configuring resistor networks with carefully selected resistance values. The four-terminal current source circuit uses depletion mode transistors to generate voltages that are independent of system voltage variations, while the temperature-compensating circuit adjusts the temperature coefficient of the reference voltage by changing the operating parameters of the transistors and resistors based on temperature conditions.
2Reliability
If the reference voltage is made independent of system voltage using a four-terminal current source circuit, then voltage stability is improved, but the circuit complexity increases
Solution Approach 1:
The four-terminal current source circuit uses depletion mode transistors that simultaneously provide voltage generation, voltage regulation, and temperature compensation functions. The same transistor structure and resistor network serve multiple purposes: generating voltages independent of system voltage, stabilizing these voltages, and compensating for temperature effects, thereby reducing the need for separate dedicated circuits for each function.
Solution Approach 2:
The four-terminal current source circuit is self-regulating through the inherent characteristics of depletion mode transistors. The circuit automatically adjusts its operation to maintain voltage independence from system voltage variations without requiring external control signals or additional regulation stages. The temperature-compensating circuit also operates autonomously, automatically correcting temperature drift based on the temperature-dependent behavior of the transistor parameters.
3Reliability
If temperature compensation is applied to the reference voltage, then temperature stability is improved, but the device complexity increases
Solution Approach 1:
The temperature compensation function is merged with the existing voltage generation and regulation circuits. The temperature-compensating circuit shares transistors and resistors with the four-terminal current source circuit and regulator circuit, rather than being a completely separate addition. This merging allows temperature compensation to be achieved using the same hardware components that are already present for voltage generation and regulation, thereby minimizing the increase in device complexity.
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
The solution provides a stable reference voltage that is independent of system voltage and temperature changes, ensuring accurate and reliable operation across a wide range of conditions, as demonstrated by simulation curves showing minimal deviation and high stability.
Implementation Method 1
the first transistor and the second transistor are depletion mode transistor
Implementation Method 2
the reference voltage outputted from the regulator circuit is independent of variation of the first system voltage via voltage difference between the first voltage and the second voltage
Implementation Method 3
the temperature-compensating circuit receives the first current and compensates temperature curve of the reference voltage outputted from the regulator circuit
Data Source
AI summary
A bandgap reference voltage generating circuit for providing a reference voltage is disclosed. The bandgap reference voltage generating circuit includes four-terminal current source circuit, a regulator circuit and a temperature-compensating circuit. The four-terminal current source circuit outputs a first voltage, a second voltage and a first current which are independent of variation of a first system voltage. The regulator circuit receives the first voltage and the second voltage and when the first system voltage is larger than a threshold voltage value, the regulator circuit outputs the reference voltage independent of variation of the first system voltage via voltage-difference between the first voltage and the second voltage. The temperature-compensating circuit receives the first current and compensates a temperature curve of the reference voltage outputted from the regulator circuit.