Current Limited Voltage Supply with Integrated Capacitor
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Solution Overview
Problem
Conventional semiconductor integrated circuits face high power consumption and noise due to high switching currents, which can hinder proper operation and introduce noise into power supply lines, and existing variable current sources struggle to balance current limitation with operational frequency requirements.
Innovation Solution
A current limited voltage supply using a transistor in a current mirror configuration with a bias circuit and an integrated capacitor, where the capacitor stores energy during non-switching intervals and discharges during switching to provide rapid energy to digital logic cells, minimizing voltage fluctuations and current spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If variable current sources are used to limit switching currents, then power consumption and noise are reduced, but the ability to operate at desired frequency is compromised
Solution Approach 1:
The capacitor is pre-charged during non-switching intervals when current demand is low. This preliminary energy storage enables the circuit to deliver high current instantaneously when switching occurs, without requiring continuously high current limits that would increase power consumption and noise during idle periods.
Solution Approach 2:
The current limit is applied periodically rather than continuously. The capacitor charges during non-switching periods and discharges during switching periods, creating a periodic current delivery pattern that reduces average power consumption while maintaining peak performance when needed.
2Object-generated harmful factors
If current flowing from standard digital logic cells is limited too much, then power consumption and noise are reduced, but the circuitry cannot operate correctly or switch at desired frequency
Solution Approach 1:
The capacitor acts as an intermediary energy storage element between the limited current source and the digital logic cells. It decouples the current limiting function from the switching function, allowing the current limit to be set low for reduced noise while the capacitor provides the necessary current bursts for correct circuit operation.
3Use of energy by stationary object
If variable current sources limit current to reduce power consumption, then DC current consumption is reduced, but the effectiveness is limited due to inability to maintain high-speed switching
Solution Approach 1:
Energy is preliminarily stored in the capacitor during low-demand periods, enabling high-speed switching during active periods without requiring continuously high DC current consumption. The capacitor is charged in advance when speed requirements are not demanding.
Solution Approach 2:
The current delivery capability is made dynamic through the capacitor's charge-discharge cycles. The system transitions between low-current (charging) and high-current (discharging) states, adapting to the instantaneous switching requirements rather than maintaining a fixed current level.
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 solution effectively reduces power consumption and noise while ensuring proper operation of digital logic cells by managing current spikes and voltage fluctuations, allowing for reliable high-speed switching and efficient power use.
Implementation Method 1
A current limited voltage supply using a transistor in a current mirror configuration with a bias circuit and an integrated capacitor, where the capacitor stores energy during non-switching intervals and discharges during switching
Data Source
AI summary
A current limited voltage supply including a transistor and a capacitor is provided for powering digital logic cells of an integrated circuit. The transistor is connected in a current mirror configuration, such that a constant reference current is mirrored through the transistor to create a first supply current. The transistor is coupled to the digital logic cells and the capacitor. The first supply current is used to charge the capacitor while the digital logic cells are not switching. While the digital logic cells are switching, the capacitor discharges to the digital logic cells, thereby providing the digital logic cells with sufficient energy to implement high-speed switching. The capacitor minimizes voltage fluctuations within in the current limited voltage supply, such that analog circuitry can be reliably powered from a different branch of the same current mirror circuit.