Load Switch Current-Limit Control for Wide-Range Loop Stability
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Solution Overview
Problem
Conventional load switch circuits fail to respond quickly and regulate load current to a desired current limit when the load changes, leading to instability in the current regulation loop, especially when the set current limit varies over a wide range.
Innovation Solution
The load switch circuit incorporates a switching element and a controlling circuit that forms a loop with a current feedback mechanism, regulating the load current to a set limit by controlling the loop gain to be linearly proportional to the current, using a differential amplifier to stabilize the loop even when the set current limit changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional load switch circuit is used, then the circuit structure is simple, but the circuit cannot respond quickly and regulate load current to desired current limit when load changes
Solution Approach 1:
The patent implements a current regulation loop that senses the load current and feeds it back to the controlling circuit. The controlling circuit compares the sensed current with a reference current and adjusts the switching element's duty cycle accordingly, enabling quick response to load changes and maintaining desired current limit through continuous feedback control
Solution Approach 2:
The patent employs a dynamic control mechanism where the controlling circuit adjusts the switching element's duty cycle in real-time based on load conditions. The circuit transitions from static conventional switching to dynamic pulse-width modulation (PWM) control, allowing the system to adapt quickly to varying load requirements and maintain stable current regulation
2Stability of the object's composition
If conventional load switch circuit is used, then the circuit structure is simple, but the current regulation loop becomes unstable when set current limit varies over wide range
Solution Approach 1:
The patent changes the operating parameters of the switching element dynamically through PWM control. By adjusting the duty cycle parameter based on the desired current limit and actual load conditions, the circuit maintains stable regulation across a wide range of current limits. The controlling circuit modifies switching parameters in real-time to adapt to different operating points
Solution Approach 2:
The current regulation loop uses feedback control to maintain stability. The sensed load current is continuously compared with the reference current, and the controlling circuit adjusts the switching element accordingly. This closed-loop feedback mechanism ensures stable current regulation even when the set current limit varies over a wide range, preventing loop instability
3Productivity
If conventional load switch circuit is used, then the device complexity is low, but the circuit cannot regulate current quickly when load changes
Solution Approach 1:
The patent replaces conventional mechanical or simple electronic switching with electronic pulse-width modulation (PWM) control. The controlling circuit uses electronic signals to modulate the switching element's duty cycle, enabling fast current regulation without mechanical moving parts. This electronic control substitution achieves rapid response while maintaining reasonable device complexity through integrated circuit implementation
Data Source
AI summary
The present invention discloses a load switch circuit including a switching element and a controlling circuit. The switching element is coupled between an input terminal and an output terminal of the load switch circuit. The controlling circuit coupled to the switching element, and is configured to regulate a set current limit of a load current flowing through the switching element. The controlling circuit is configured to control a loop formed by the controlling circuit and the switching element based on a sensed signal indicative of the current flowing through the switching element, so that the loop remains stable when the set current limit is changed from a first set current limit to a second set current limit. The load switch circuit provided by the present invention can stabilize the current regulation loop even when the set current limit changes in a larger dynamic range.