Oxide Semiconductor Charge Pump for Stable Negative Potential
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Solution Overview
Problem
Existing semiconductor devices face challenges in generating and stabilizing negative potentials with high accuracy, comparing negative potentials directly, and reducing power consumption while operating with a single power source.
Innovation Solution
A semiconductor device comprising a first and second transistor, a capacitor, and a comparator, where the transistors contain oxide semiconductors, and a charge pump is used to generate and manage the negative potential, allowing for direct comparison and stable potential holding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a charge pump circuit is used to generate negative potential, then negative potential can be generated, but the accuracy and stability of the negative potential are difficult to control
Solution Approach 1:
The patent employs a feedback mechanism where a comparator detects the actual negative potential generated by the charge pump and compares it with a reference voltage. Based on this comparison, the control circuit adjusts the charge pump operation to maintain the negative potential at the desired level, thereby achieving high accuracy without excessive complexity
Solution Approach 2:
The patent introduces an intermediary conversion process where the negative potential is first converted to a positive voltage, then compared with a reference voltage to generate a detection signal. This intermediary approach simplifies the control mechanism while maintaining high precision in negative potential generation
2Adaptability or versatility
If multiple power sources are used to generate positive and negative potentials, then both polarities can be supplied, but the device complexity and power consumption increase
Solution Approach 1:
The patent makes a single positive power source serve multiple functions: it directly provides positive potential to circuits requiring positive voltage, and simultaneously serves as the reference for generating negative potential through the charge pump and voltage conversion circuitry. This eliminates the need for separate negative power sources while maintaining full functionality
Solution Approach 2:
The system uses the available positive power source to generate the negative potential it needs through the charge pump circuit, rather than relying on an external negative power source. The circuit essentially creates its own negative supply from the positive supply, reducing overall system complexity
3Reliability
If conventional transistors are used in comparator circuits, then the circuit can operate, but power consumption is high
Solution Approach 1:
The patent changes the fundamental operating parameters of the comparator by using oxide semiconductor transistors instead of conventional transistors. This material substitution fundamentally alters the power consumption characteristics while maintaining the comparator's ability to detect and compare voltages, achieving low power consumption without sacrificing reliability
Data Source
AI summary
A potential is held stably. A negative potential is generated with high accuracy. A semiconductor device with a high output voltage is provided. The semiconductor device includes a first transistor, a second transistor, a capacitor, and a comparator. The comparator includes a non-inverting input terminal, an inverting input terminal, and an output terminal. A gate and one of a source and a drain of the first transistor are electrically connected to each other. One of a source and a drain of the second transistor is electrically connected to the non-inverting input terminal of the comparator, one electrode of the capacitor, and a gate of the second transistor. The other of the source and the drain of the second transistor is electrically connected to the one of the source and the drain of the first transistor. The first transistor and the second transistor each contain an oxide semiconductor.