Power-On Reset Circuit for Accurate Low-Voltage Detection
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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 configuration using NPN type bipolar transistors, resistance elements, and a comparator with a PMOS transistor, which adjusts detection voltage and suppresses temperature and offset variations, allowing for accurate detection at lower voltages with reduced 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 is poor and power consumption is high
Solution Approach 1:
The patent changes the detection mechanism by using a bipolar transistor's base-emitter voltage (Vbe) as a temperature-compensated reference, replacing conventional voltage divider networks. This parameter change enables accurate detection at lower voltages while maintaining stability across temperature variations, directly resolving the contradiction between detection accuracy and power consumption.
Solution Approach 2:
The patent introduces a bipolar transistor as an intermediary element that converts temperature-dependent voltage variations into a stable reference signal. The transistor's Vbe characteristic acts as a mediator that compensates for temperature effects on the detection threshold, enabling accurate low-voltage detection without requiring high-power reference circuits.
2Duration of action of moving object
If the operational lower limit voltage is reduced to extend battery life, then battery life improves, but detection of the lower voltage becomes difficult
Solution Approach 1:
The patent changes the detection threshold parameter by using the bipolar transistor's Vbe voltage (approximately 0.6-0.7V) as the reference level. This enables the power-on reset circuit to accurately detect and respond to supply voltages at the 1.2V level, allowing the device to operate at lower voltages that extend battery life while maintaining reliable detection capability.
3Reliability
If temperature variations are present, then the detection voltage drifts due to offset variations, but stable detection is required
Solution Approach 1:
The bipolar transistor serves as a temperature-compensating intermediary by introducing a voltage element (Vbe) that has opposite temperature dependence to the voltage divider network. This mediator cancels out temperature-induced drift, maintaining stable detection thresholds across temperature variations and ensuring reliable operation.
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 achieves improved detection voltage accuracy and reduced power consumption, enabling longer battery life and extended operational time in semiconductor devices by effectively detecting lower operational voltages.
Implementation Method 1
a first voltage generating circuit including an NPN type bipolar transistor, the second resistance element and a third resistance element connected in series between a power supply voltage and a ground voltage, the bipolar transistor generating a voltage proportional to a temperature
Implementation Method 2
a comparator comparing a voltage obtained by dividing the power supply voltage with a voltage generated by the bipolar transistor
Data Source
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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.