Low Voltage Reference Circuit Using Current Mirror Topology
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Solution Overview
Problem
Existing voltage reference and oscillator circuits face challenges in operating at low power supply voltages, particularly below 1.1V, due to complexity and high power consumption, limiting their suitability for sub-bandgap and low voltage applications, and require simplification to reduce current branches and voltage requirements.
Innovation Solution
A voltage reference and oscillator circuit design utilizing a current mirror function with a voltage generator and current drive network, featuring a reduced number of branches and avoiding the need for multiple MOSFET drain-to-source and gate-to-source voltages, allowing operation from 1.1V to 3.6V with low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional bandgap voltage reference circuits are used, then stable reference voltage is achieved, but minimum operating voltage is limited to about 1.4V
Solution Approach 1:
The patent changes the fundamental operating parameters by using sub-bandgap voltage (below 1.25V) instead of traditional bandgap voltage, and employs a different circuit topology that operates with single or dual MOSFET stacks rather than the complex multi-transistor bandgap circuitry, enabling operation at minimum voltages of 1.1V or 1.2V while maintaining reference stability
2Use of energy by moving object
If voltage reference circuits operate at low power supply voltages (1.1V), then power consumption is reduced, but circuit complexity increases and reliability decreases
Solution Approach 1:
The patent segments the voltage reference function into separate modular blocks: a core sub-bandgap reference generator, a voltage regulator stage, and an optional oscillator module. This segmentation allows each block to be optimized independently and enables flexible configuration to reduce overall circuit complexity while maintaining low voltage operation
Solution Approach 2:
The patent introduces intermediate voltage regulation stages and buffer circuits that mediate between the low-voltage reference core and higher-voltage system requirements, allowing the complex low-voltage reference to drive simpler higher-voltage circuitry, thereby reducing overall system complexity
3Reliability
If multiple MOSFET stacks are used for voltage tolerance, then power supply voltage tolerance is improved, but voltage requirements increase
Solution Approach 1:
The patent employs dynamic voltage regulation where the number and configuration of MOSFET stacks are adaptively controlled based on the actual power supply voltage level. The circuit can dynamically switch between different operational modes (single-stack, dual-stack, or stacked MOSFET configurations) to maintain proper voltage tolerance without requiring a fixed high minimum voltage, thereby reducing overall voltage requirements while preserving reliability
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 enables efficient operation at low power supply voltages with reduced complexity, lower power consumption, and improved voltage tolerance, simplifying the circuit structure and enhancing performance across a wide voltage range.
Implementation Method 1
a current mirror function providing matching and sourcing network branches
Implementation Method 2
a voltage generator network sourced from said current mirror providing a base-emitter voltage
Data Source
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AI summary
An apparatus and method for a voltage reference circuit and oscillator which operates for a low voltage power supply. The voltage reference circuit is used in an "always on" mode of operation, and have low power usage. The operational range is 1.1V to 3.6 V, and must allow for sub-bandgap voltage conditions as well as voltage tolerant for higher voltages. The circuit minimizes the number of current branches by avoiding complexity of operational amplifiers and comparator networks. The circuit avoids stacking of more than 2 devices to allow for low voltage operation. The voltage reference circuit between a power supply node and a ground node and configured for generating a reference voltage comprises of a current mirror function providing matching and sourcing network branches, a voltage generator network sourced from a current mirror providing a baseemitter voltage, a current drive function network electrically sourced from a current mirror function, and an output network function sourced from a current mirror providing a voltage reference output voltage. An oscillator circuit between a power supply node and a ground node and configured for generating an oscillating signal comprises of a current mirror function providing matching and sourcing network branches, a current drive function network electrically sourced from said current mirror function, an output network function sourced from said current mirror providing a capacitors, current sources, a capacitor providing charge storage , and output network function, and, a feedback loop network providing reset function.