Band-gap Reference Voltage Detection Circuit for POR
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Solution Overview
Problem
Existing power-on reset (POR) circuits in electronic systems face challenges in reliably determining the adequacy of the supply voltage for proper functionality, especially at low voltages and varying temperatures, often requiring multiple circuits or increased circuit real estate, and struggle to handle fast or slow voltage rise times.
Innovation Solution
A band-gap reference voltage detection circuit using a Brokaw cell with a threshold detection mechanism that applies input voltage to transistor bases, allowing for reliable threshold detection insensitive to temperature and process variations, and capable of operating with a single circuit to provide multiple trip points for different voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple POR circuits are used to supervise multiple voltage supply thresholds, then the voltage supply requirements of different circuits are satisfied, but the circuit real estate increases and costs increase
Solution Approach 1:
The single POR circuit is designed to provide multiple trip points by utilizing a voltage divider network with multiple tap points. Each tap point can be connected to a different internal circuit, allowing one circuit to supervise multiple voltage thresholds. This multi-functional design eliminates the need for separate POR circuits for each voltage threshold, thereby reducing circuit real estate while maintaining comprehensive voltage supervision.
Solution Approach 2:
The voltage divider network is segmented into multiple sections with different tap points, each providing a different voltage threshold. This segmentation allows the single POR circuit to detect different voltage levels by selecting appropriate tap points, effectively creating multiple independent threshold detection capabilities within one unified circuit structure.
2Area of stationary object
If a single voltage threshold is selected to satisfy all dependent circuits, then circuit real estate is reduced, but some circuits with lower acceptable voltage thresholds are delayed in power-up
Solution Approach 1:
The POR circuit incorporates dynamic threshold selection capability through a voltage divider network with multiple tap points. Instead of a fixed single threshold, the circuit can dynamically select different trip points based on the specific requirements of internal circuits. This dynamic adaptability ensures that each internal circuit receives a reset signal at the appropriate voltage threshold, preventing power-up delays while maintaining compact circuit design.
3Device complexity
If POR circuit is powered by the same voltage source it monitors, then circuit complexity is reduced, but the circuit struggles to determine adequacy at low voltages
Solution Approach 1:
The voltage divider network acts as an intermediary between the voltage source and the POR circuit. It transforms the input voltage into multiple scaled-down versions through resistive division, allowing the POR circuit to monitor different voltage thresholds. This intermediary structure enables the POR circuit to function reliably at low voltages by providing appropriate voltage levels for comparison, while the circuit remains powered by the same voltage source it monitors.
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 reliable detection of the input voltage threshold, maintaining stability across temperature and process variations, and reduces circuit complexity by using a single band-gap reference voltage detection circuit to provide multiple power-on reset signals, thus optimizing circuit real estate and cost.
Implementation Method 1
A band-gap reference voltage detection circuit using a Brokaw cell with a threshold detection mechanism that applies input voltage to transistor bases, allowing for reliable threshold detection insensitive to temperature and process variations
Data Source
AI summary
Methods, devices, modules, and systems for a band-gap reference voltage detection circuit are provided. One embodiment for a band-gap reference voltage detection circuit includes a Brokaw cell having a band-gap reference voltage, and a circuit portion for indicating the magnitude of an input voltage signal with respect to the band-gap reference voltage. The input voltage is applied to transistor bases of the Brokaw cell.