Charge Pump Slew-Rate Control via Negative Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Prior art switched capacitor circuits experience large spikes in drain-source current when switching transistors transition from OFF to ON, leading to unwanted Electromagnetic Interference (EMI) noise due to high slew rates of in-rush currents.
Innovation Solution
The implementation of a negative feedback mechanism using a capacitor connected to the output port and a transconductance amplifier to control the slew rate of the drain-source current of switching transistors, reducing the in-rush current spikes by injecting current based on the time derivative of the output voltage, thereby mitigating EMI noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If switching transistors are switched from OFF to ON in prior art switched capacitor circuits, then the circuit operates and provides current to the load, but large spikes in drain-source current (in-rush currents) are generated causing unwanted EMI noise
Solution Approach 1:
A feedback mechanism is implemented using a capacitor connected between the output port and a node in the circuit. This capacitor injects current based on the time derivative of the output voltage, creating a negative feedback loop that actively reduces the slew rate of in-rush currents when switching transistors transition from OFF to ON, thereby mitigating EMI noise while maintaining circuit operation
Solution Approach 2:
The feedback mechanism anticipates the in-rush current spikes by detecting the time derivative of the output voltage. By acting before the full current spike occurs, the circuit preemptively reduces the slew rate of the in-rush current, preventing the harmful EMI noise from generating in the first place
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 the slew rate of in-rush currents, minimizing EMI noise and enabling a soft ramp-up of switched capacitor circuits while maintaining power efficiency by adjusting the voltage gain and load current.
Implementation Method 1
The implementation of a negative feedback mechanism using a capacitor connected between the output port and a node, which injects current based on the time derivative of the output voltage
Data Source
AI summary
A ramp-up circuit for switched capacitor circuits with negative feedback to control the slew rate of in-rush current. Other embodiments are described and claimed.