Voltage Detection Circuit with Temperature-Compensated Reference
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Solution Overview
Problem
Existing voltage detection circuits in charge pump systems, particularly in DRAM chips, face inaccuracies in measuring negative voltages due to disturbances in power supply voltage and transistor threshold voltage variations, affecting detection accuracy.
Innovation Solution
A voltage detection circuit that utilizes a reference voltage generated by combining a first voltage with a positive temperature coefficient and a second voltage with a negative temperature coefficient, ensuring that temperature-induced changes cancel each other out, thereby stabilizing the reference voltage and improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a transistor superposition mode is used to raise the voltage to be measured, then the voltage can be elevated for comparison, but the raised voltage generates large deviation due to power supply disturbance and transistor threshold voltage random deviation, reducing detection accuracy
Solution Approach 1:
The patent changes the parameter of reference voltage generation by using a bandgap reference circuit that generates a reference voltage with positive temperature coefficient to compensate for the negative temperature coefficient of the voltage to be measured, thereby stabilizing the difference voltage against temperature and power supply variations
Solution Approach 2:
The patent introduces an operational amplifier as an intermediary component to accurately amplify the difference voltage between the raised voltage and reference voltage, preventing the amplification of noise and deviations that would occur with direct transistor superposition
2Measurement precision
If the voltage to be measured is directly compared with reference voltage, then the detection process is simple, but the detection accuracy is low due to temperature influence and power supply disturbance
Solution Approach 1:
The patent segments the voltage detection process into distinct functional modules: a voltage raising circuit that raises the voltage to be measured by a fixed amount, a reference voltage generation circuit that provides temperature-compensated reference, and a comparison circuit that detects the difference, allowing each module to be optimized independently
Solution Approach 2:
The patent changes the temperature characteristic parameter of the reference voltage to be positive, which compensates for the negative temperature coefficient of the voltage to be measured, thereby maintaining detection accuracy across temperature variations without requiring complex temperature sensing and compensation circuits
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
This approach effectively stabilizes the reference voltage, allowing for accurate measurement of negative voltages without temperature influence, enhancing detection accuracy in charge pump circuits.
Implementation Method 1
a transistor superposition mode is usually used in the voltage detection circuit to raise the voltage to be measured
Implementation Method 2
the reference voltage is generated by a bandgap reference circuit, in which a temperature coefficient compensation function is built in
Data Source
AI summary
A voltage detection circuit and a charge pump circuit using the voltage detection circuit are provided. The voltage detection circuit includes: a voltage raising circuit configured to adjust a voltage to be measured and then output an adjusted voltage, where the adjusted voltage is equal to the sum of the voltage to be measured and a reference voltage; and the reference voltage is generated by a combination of a first voltage with a positive temperature coefficient and a second voltage with a negative temperature coefficient.