Power-On Reset Circuit With Vbe Compensation for Low-Voltage Sensing
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Solution Overview
Problem
Existing power-on reset circuits in semiconductor devices face challenges in detecting lower operational voltages, leading to poor detection voltage accuracy and high power consumption, which affects battery life and operational time in IoT equipment.
Innovation Solution
A power-on reset circuit design incorporating a first and second bipolar transistor, detection-voltage adjusting resistance elements, temperature-characteristic adjusting resistance elements, and a comparator, which adjusts the detection voltage and reduces variations, allowing the circuit to operate at lower voltages while minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional power-on reset circuits are used, then the circuit can detect power-on voltage, but the detection voltage accuracy deteriorates at lower operational voltages
Solution Approach 1:
The patent changes the detection mechanism by using a bipolar transistor's base-emitter voltage (Vbe) as a temperature-compensated reference voltage, which has a negative temperature coefficient. This allows the detection voltage to be accurately set at lower operational voltages by leveraging the inherent physical characteristics of the bipolar transistor rather than relying on conventional voltage divider networks that lose accuracy at low voltages.
Solution Approach 2:
The patent compensates for temperature effects on detection voltage by introducing a temperature compensation circuit that uses the negative temperature coefficient of the bipolar transistor's Vbe voltage. This counteracts the positive temperature coefficient of other circuit elements, maintaining stable detection voltage accuracy across temperature variations even at lower operational voltages.
2Duration of action of moving object
If the operational lower limit voltage is reduced to extend battery life, then battery life is improved, but detection voltage accuracy deteriorates
Solution Approach 1:
The patent enables operation at lower voltages by changing the detection mechanism to use the bipolar transistor's Vbe voltage, which provides a stable reference even at low supply voltages. This allows the operational lower limit voltage to be reduced while maintaining accurate power-on detection, thereby extending battery life without sacrificing detection accuracy.
3Device complexity
If conventional detection circuits are used, then the circuit structure is simple, but power consumption is high
Solution Approach 1:
The bipolar transistor's base-emitter junction serves its own purpose as both a switching element and a voltage reference source. The Vbe voltage naturally provides the temperature-compensated reference voltage needed for accurate detection, eliminating the need for separate reference voltage generation circuits and reducing overall power consumption while maintaining simplicity.
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 accurate detection of lower operational voltages, reduces power consumption, and extends battery life by allowing the semiconductor device to operate efficiently across a wider voltage range with improved detection accuracy and reduced variations.
Implementation Method 1
a first bipolar transistor; a second bipolar transistor configured by connecting a plurality of bipolar transistor in parallel; a detection-voltage adjusting resistance element; a temperature-characteristic adjusting resistance element
Data Source
AI summary
To provide a technique for detecting a low voltage of a power-on reset circuit. A semiconductor device has a power-on reset circuit including: a first bipolar transistor; a second bipolar transistor formed by connecting a plurality of bipolar transistors in parallel; a detection-voltage adjusting resistance element; a temperature-characteristic adjusting resistance element; a current adjusting resistance element; and a comparator.