Oxide Semiconductor Holding Circuit for Reference Voltage Power Reduction
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Solution Overview
Problem
Conventional semiconductor devices with signal processing circuits, such as voltage regulators, continue to consume power even when current is low, as the reference voltage generation circuit operates continuously, leading to insufficient reduction in power consumption.
Innovation Solution
Incorporating a semiconductor device with a reference voltage generation circuit, a voltage divider circuit, an operational amplifier, bias circuits, and holding circuits with transistors having extremely small off-state current, specifically using oxide semiconductor transistors with wider band gaps than silicon, allowing the reference voltage generation circuit to be switched off and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the reference voltage generation circuit operates continuously to maintain stable voltage output, then voltage stability is improved, but power consumption increases
Solution Approach 1:
The patent applies dynamics by making the reference voltage generation circuit switchable between active and inactive states. The circuit is activated only when voltage regulation is needed and deactivated when not needed, transforming a static continuous operation system into a dynamic conditional operation system. This resolves the contradiction by allowing voltage stability when required while reducing power consumption when not required.
Solution Approach 2:
The patent applies local quality by using oxide semiconductor transistors specifically in the reference voltage generation circuit where low off-state current is critical. This localized application of special material properties (oxide semiconductor with wide band gap) to the specific circuit section that benefits most from low leakage current allows the circuit to maintain stability with minimal power consumption.
2Ease of manufacture
If conventional silicon-based transistors are used in the holding circuit, then manufacturing ease is improved, but off-state current remains too high to enable complete power shutdown
Solution Approach 1:
The patent applies parameter changes by transitioning from silicon-based transistors to oxide semiconductor transistors, fundamentally changing the material parameter (band gap width). Oxide semiconductors have a wider band gap than silicon, which directly results in exponentially lower off-state current. This parameter change enables the holding circuit to maintain voltage levels with negligible power consumption, allowing complete shutdown of the reference voltage generation circuit.
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 effectively reduces power consumption in signal processing circuits by enabling the reference voltage generation circuit to stop operating, thereby minimizing power usage during low current conditions, with the oxide semiconductor transistors providing significantly lower off-state current densities compared to silicon-based transistors.
Implementation Method 1
A transistor with significantly small off-state current is used as each of the switches. As the transistor with extremely small off-state current, a transistor whose channel is formed in a film or a substrate including a semiconductor having a wider band gap than silicon can be used.
Data Source
AI summary
Power consumption of a signal processing circuit is reduced. Further, power consumption of a semiconductor device including the signal processing circuit is reduced. The signal processing circuit includes a reference voltage generation circuit, a voltage divider circuit, an operational amplifier, a bias circuit for supplying bias current to the operational amplifier, and first and second holding circuits. The first holding circuit is connected between the reference voltage generation circuit and the bias circuit. The second holding circuit is connected between the voltage divider circuit and a non-inverting input terminal of the operational amplifier. Reference voltage from the reference voltage generation circuit and reference voltage from the voltage divider circuit can be held in the first and second holding circuits, respectively, so that the reference voltage generation circuit can stop operating. Thus, power consumption of the reference voltage generation circuit can be reduced.