Buffer Circuit Power Switching for Stable Internal Supply Voltage
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Solution Overview
Problem
The existing buffer circuits in semiconductor integrated circuits suffer from significant variations in internal power supply voltage due to driving currents, leading to potential malfunctions or shutdowns in peripheral circuits, as they fail to effectively suppress voltage variations despite the use of voltage regulators intended to provide constant voltage.
Innovation Solution
A logic circuit with a buffer unit, voltage detection unit, and switch unit configuration that connects the buffer unit to the power supply based on voltage detection signals, allowing it to switch between external and internal power supplies during changes in input signal levels, thereby reducing voltage variations by managing driving currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a buffer circuit uses a voltage regulator to provide constant internal power supply voltage, then the power supply stability is improved, but the voltage still varies due to driving currents from the buffer circuit
Solution Approach 1:
The buffer circuit dynamically switches between internal power supply (from voltage regulator) and external power supply based on the operation state. When the buffer is in high-drive state, it switches to external power supply to prevent voltage drops. This dynamic switching resolves the contradiction by adapting the power supply source to the instantaneous current demands, maintaining both voltage stability and operational reliability.
Solution Approach 2:
A power supply switching mechanism acts as an intermediary between the voltage regulator and the buffer circuit. This intermediary detects voltage drops or high current demands and switches the power supply source accordingly, preventing the direct negative impact of driving currents on the regulated voltage, thus maintaining both stability and reliability.
2Loss of energy
If delay difference generators are used to reduce through current, then power consumption is reduced, but voltage variations due to driving currents still occur
Solution Approach 1:
The circuit dynamically switches power supply sources based on instantaneous current demands. Even though delay difference generators reduce average through current, the dynamic switching ensures that during high-drive periods when voltage drops occur, the buffer switches to external power supply, maintaining voltage stability while preserving the energy-saving benefit of reduced average current.
3Stability of the object's composition
If the buffer circuit switches power supply during input signal changes, then voltage variations are reduced, but circuit complexity increases
Solution Approach 1:
The power supply switching mechanism uses feedback from voltage detection or current demand detection to automatically switch between internal and external power supplies. This feedback-based approach maintains voltage stability without requiring complex manual control, as the switching is autonomously determined by the circuit's own operational state.
Solution Approach 2:
The buffer circuit autonomously manages its own power supply by detecting its own current demands and switching sources accordingly. This self-service mechanism reduces the need for external voltage regulation complexity while maintaining stable output voltage, as the circuit itself determines when to switch power sources based on its operational needs.
Data Source
AI summary
Provided is a logic circuit that can reduce the variation of a power supply voltage supplied thereto and a semiconductor integrated circuit including the logic circuit. The logic circuit includes a buffer unit, a voltage detection unit, and a switch unit. The buffer unit is connected between a first power supply or a voltage regulator and a second power supply to receive power supply, and outputs a signal having the same or inverted logic level as an input signal to an output terminal. The voltage detection unit detects a voltage at the output terminal and outputs a detection signal based on a detection result. The switch unit connects the buffer unit to the first power supply or the voltage regulator in accordance with the detection signal.