Adaptive Power Source Multiplexer for Fast Low-Droop Switching
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Solution Overview
Problem
Current power source multiplexers experience voltage droops and excessive inrush currents during transitions between input power sources, leading to potential system resets and inefficiencies.
Innovation Solution
The implementation of adaptive switch controls, including boost circuits to enhance current during switching and reverse current blocking to delay transitions until voltage thresholds are met, mitigates inrush currents and voltage drooping by reducing switching time and ensuring stable power delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simple power switches and logic are used to select input sources, then device complexity is reduced, but voltage droops and excessive inrush currents occur during transitions
Solution Approach 1:
The boost circuit is activated before the actual switching occurs to pre-charge the output capacitor and prepare the circuit for the incoming power source. This preliminary action ensures that when the switch transitions, the output voltage remains stable and inrush currents are minimized, as the circuit is already prepared to accept the new power source without sudden voltage drops or current spikes.
Solution Approach 2:
The driver circuit dynamically adjusts the switching parameters based on the transition state. During normal operation, switches are controlled with standard timing, but during power source transitions, the driver circuit modifies the switching waveform to include a boosted current phase followed by a controlled decay phase. This parameter change allows the system to maintain stability during transitions while returning to normal operation afterward.
2Productivity
If fast switching is implemented to ensure seamless power transition, then productivity is improved, but excessive inrush current flows through switch devices
Solution Approach 1:
The switching process is divided into distinct periodic phases: a boost phase where current is rapidly increased to quickly establish the new power connection, followed by a decay phase where the current is controlled to reduce to steady-state levels. This periodic action allows the system to achieve fast switching overall while managing inrush current through controlled temporal distribution of the current profile.
Solution Approach 2:
The boost circuit enables the system to rush through the critical transition period by providing a high current pulse that quickly charges the output capacitor and establishes the new power source connection. This rushing through the transition phase minimizes the time the system spends in an unstable state, thereby maintaining productivity while the controlled duration of the boost phase prevents excessive inrush current damage.
3Use of energy by moving object
If steady-state current is used for switching, then energy consumption is reduced, but switching time increases causing voltage droops
Solution Approach 1:
The driver circuit implements dynamic current control by switching between two operational modes: a boost mode where current is increased to high levels for rapid switching, and a steady-state mode where current returns to normal consumption levels. This dynamic adjustment allows the system to use high current only when necessary during the transition phase, then immediately return to energy-efficient operation, thereby achieving fast switching without permanent increase in energy consumption.
Solution Approach 2:
The boost circuit applies excessive current temporarily during the switching transition to ensure rapid and clean power source switching, but this excessive action is limited to a controlled time period. After the transition is complete, the current is reduced back to steady-state levels. This partial application of excessive action achieves the necessary switching speed while minimizing energy consumption by limiting the high-current phase to only when absolutely necessary.
Data Source
AI summary
A power source multiplexer includes a first switch circuit connected between a first input voltage source node and an output voltage node. A second switch circuit is connected between a second input voltage source node and the output voltage node. A driver circuit is configured to provide a steady-state current to drive one of the first or second switch circuits to electrically connect the respective input voltage source node to the output voltage node. A boost circuit is configured to boost the steady-state current for a switching time interval when switching from one of the input voltage source nodes being connected to the output node to the other of the input voltage source nodes being connected to the output voltage node.