Feedback-Controlled Power Switching for Inrush-Limited Charging
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Solution Overview
Problem
Conventional power switching circuits face challenges in designing a power switch that is small enough to limit inrush current while being large enough to charge an internal power supply within a specified time period.
Innovation Solution
The power switching circuitry includes a primary power switch and multiple auxiliary power switches, with a voltage detection circuit that monitors the voltage at the output node and selectively activates additional auxiliary power switches based on the detected voltage, ensuring efficient charging of the internal power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single small power switch is used to limit inrush current, then inrush current is limited, but the charging time of internal power supply exceeds the specified period
Solution Approach 1:
The power switch is divided into multiple switches (first power switch, second power switch, third power switch) with different sizes. The first power switch is small to limit inrush current, while the second and third power switches are larger to provide additional charging current. This segmentation allows the system to simultaneously achieve inrush current limitation and fast charging by activating different switches at different stages of the charging process.
2Productivity
If a single large power switch is used to charge internal power supply quickly, then charging time is reduced, but inrush current exceeds acceptable limits
Solution Approach 1:
The system dynamically adjusts the charging configuration by sequentially activating different power switches based on the charging stage. Initially, only the small first power switch is activated to limit inrush current. As the internal power supply voltage rises above the threshold, the larger second and third power switches are activated to increase charging current. This dynamic adjustment allows the system to adapt to different charging requirements at different stages.
Solution Approach 2:
The system uses a threshold detection mechanism that monitors the internal power supply voltage and provides feedback to control the activation of power switches. When the voltage rises above a predetermined threshold, this feedback signal triggers the activation of additional power switches. This feedback control ensures that larger switches are only activated when safe to do so, thereby maintaining both inrush current limitation and charging efficiency.
Data Source
AI summary
An integrated circuit may be provided with power switching circuitry. The power switching circuitry may include a primary power switch and multiple auxiliary power switches. A power gating control circuit may output control signals for selectively activating the primary power switch and at least one of the auxiliary power switches to charge a gated voltage. One or more voltage detectors may be configured to monitor the gated voltage and to activate the remaining auxiliary power switches in response to detecting that the gated voltage exceeds one or more thresholds. Configured and operated in this way, inrush current surge protection can be achieved while charging up the gated voltage sufficiently fast.