Dual Control Load Switch for Fast Turn-Off and Low Static Current
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Solution Overview
Problem
Existing load switches face challenges in achieving fast turn-off capabilities while maintaining low static current consumption, which is essential for reducing power requirements.
Innovation Solution
The implementation of a load switch with a switch element and dual control circuits, where the first control circuit quickly turns off the switch element in response to a turn-off signal, and the second control circuit maintains the switch element in the off-state using a keep-off signal, thereby minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a level shifter circuit is used to provide the gate control signal for switching the high-voltage transistor, then the load switch can be controlled, but the switching speed is slow and static current consumption is high
Solution Approach 1:
The control circuit is divided into two separate circuits: a first control circuit for fast turn-off operation and a second control circuit for maintaining the off-state. This segmentation allows each circuit to be optimized for its specific function, with the first circuit providing rapid switching and the second circuit ensuring low static current consumption during the off-state, thereby resolving the contradiction between switching speed and power consumption.
2Speed
If a single control circuit is used to switch the high-voltage transistor, then the circuit complexity is low, but the turn-off capability is not fast enough
Solution Approach 1:
The control functionality is segmented into two dedicated circuits: the first control circuit handles the critical fast turn-off operation, while the second control circuit maintains the off-state. This segmentation enables the turn-off speed to be significantly improved without requiring a single overly complex circuit, as each sub-circuit can be designed and optimized independently for its specific purpose.
Solution Approach 2:
Both control circuits share the common function of controlling the gate terminal of the high-voltage transistor, but they specialize in different aspects: one for rapid switching and another for state maintenance. This multi-functionality approach allows the system to achieve fast turn-off capability while keeping each individual circuit relatively simple and manageable.
Data Source
AI summary
A load switch includes a switch element and first and second control circuits. The switch element has an input terminal for receiving an input voltage, an output terminal for providing an output voltage, and a control terminal for receiving a switch signal, which turns the switch element on and off. The first control circuit is connected to the control terminal of the switch element and turns off the switch element in response to a first control signal. The second control circuit also is connected to the control terminal of the switch element and keeps the switch element turned off, after the first control circuit has turned off the switch element.