Low-Voltage Bandgap Reference Circuit for Stable 1 V Output
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Solution Overview
Problem
Existing memory sub-systems face challenges in generating a stable output reference voltage that is insensitive to temperature and power supply variations, particularly when the supply voltage approaches 1 volt, limiting their dynamic range and usability in low-power portable devices.
Innovation Solution
A low voltage bandgap-based output reference voltage circuit is developed, utilizing a folded cascode operational amplifier with PMOS and NMOS inputs, which generates a temperature-insensitive reference voltage by leveraging currents inversely proportional or proportional to absolute temperature, passed through resistors, to maintain stability across process, voltage, and temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional output reference voltage circuit is used, then the circuit can operate at higher supply voltages, but the dynamic range is limited and the circuit cannot operate when supply voltage approaches 1 volt
Solution Approach 1:
The patent changes the operating parameters of the bandgap reference circuit by using a folded cascode operational amplifier topology with PMOS and NMOS inputs, allowing the circuit to operate reliably at supply voltages as low as 1 volt while maintaining reference voltage stability. This parameter change enables extended adaptability without sacrificing reliability
Solution Approach 2:
The circuit dynamically adapts to different supply voltage conditions through its folded cascode architecture, which automatically adjusts its operating point and gain characteristics to maintain stable reference voltage output across a wide voltage range from 1 volt to higher voltages
2Use of energy by moving object
If the supply voltage is reduced to enable low-power portable devices, then power consumption decreases, but the dynamic range becomes smaller and reference voltage generation becomes difficult
Solution Approach 1:
The patent changes the circuit topology parameters to enable operation at ultra-low supply voltages (1 volt and below) while maintaining adequate dynamic range. The folded cascode operational amplifier with complementary PMOS/NMOS inputs is specifically designed to operate efficiently at these low voltages, allowing portable devices to achieve low power consumption without sacrificing the ability to generate stable reference voltages
Solution Approach 2:
The patent replaces conventional reference voltage generation mechanisms with a bandgap-based circuit using folded cascode operational amplifiers, which are inherently more suitable for low-voltage operation. This substitution enables the circuit to maintain reference voltage stability at supply voltages as low as 1 volt, thereby supporting low-power portable applications while preserving dynamic range
3Stability of the object's composition
If a temperature-insensitive reference voltage is generated using bandgap circuit, then temperature stability improves, but the circuit complexity increases
Solution Approach 1:
The patent segments the reference voltage generation function into modular folded cascode operational amplifier blocks with distinct PMOS and NMOS input stages. This segmentation achieves temperature-insensitive reference voltage through the bandgap principle while organizing the circuit into manageable modules, thereby reducing overall complexity compared to monolithic designs
Solution Approach 2:
The patent merges the PMOS and NMOS operational amplifier inputs into a unified folded cascode architecture that generates the bandgap reference voltage. This merging achieves temperature compensation through the inherent properties of the combined transistor pairs, providing stable reference voltage with reduced circuit complexity by integrating multiple functions into a single cohesive structure
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, low voltage reference voltage with minimal variation, enabling operation across a wide range of temperatures and power supply levels, enhancing the performance and reliability of memory sub-systems in low-power portable devices.
Implementation Method 1
generates a temperature-insensitive reference voltage by leveraging currents inversely proportional or proportional to absolute temperature, passed through resistors
Data Source
AI summary
An example apparatus can be a low voltage bandgap circuit that includes a bandgap core portion. The bandgap core portion includes an operational amplifier (op-amp). The op-amp includes a PMOS input and an NMOS input. Further, the op-amp is a folded cascode op-amp. The bandgap core portion further includes a first diode coupled to the op-amp. The bandgap core portion further includes a second diode coupled to the op-amp through a resistor.