Power Sequence Control for Cascading Semiconductor Power-Off
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Solution Overview
Problem
Semiconductor devices face challenges in controlling power sources during power-off operations, leading to delayed shutdown times and reduced responsiveness due to voltage level decreases and capacitor discharge characteristics, resulting in slower power-off times compared to power-on times.
Innovation Solution
A semiconductor device with a power sequence controller that groups power sources and initiates power-off operations in a cascading manner, starting with one group when a specific voltage level is reached or a reference time has passed, allowing for staggered power-off stages to maintain stability and reduce overall power-off time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power-off control is performed following all the sequences as in a power-on operation, then power sources are controlled at fine levels to prevent inrush current and ensure stable power supply, but the power-off time becomes slower than the power-on time by dozens to several hundred times
Solution Approach 1:
The patent divides power sources into multiple groups (first power source group, second power source group, third power source group) and implements staged power-off control where each group is powered off sequentially at different times. This segmentation allows the system to maintain fine-level control for reliability while reducing overall power-off time by not waiting for all power sources to discharge completely.
Solution Approach 2:
The patent performs preliminary actions by starting the power-off operation of subsequent power source groups before the previous groups are completely powered off. Specifically, the second power source group starts power-off when the first group's voltage reaches a first reference voltage, and the third group starts when the second group's voltage reaches a second reference voltage, enabling overlapping discharge processes.
2Productivity
If voltage levels of power sources decrease due to discharge when powered-off, then power-off operation can proceed, but the amount of time to completely power-off the power sources is delayed differently by capacitor charge amounts, resistance magnitudes, and external capacitance
Solution Approach 1:
The patent implements feedback control by monitoring the voltage levels of power source groups and using these measurements to trigger subsequent power-off actions. The power-off of the second group is triggered when the first group's voltage reaches a first reference voltage, and the third group's power-off is triggered when the second group's voltage reaches a second reference voltage, creating a feedback-based cascading power-off sequence.
3Reliability
If power sources are controlled at fine levels during power-off operation, then inrush current is prevented and stable power supply is maintained, but responsiveness and reaction speed become poor
Solution Approach 1:
The patent applies dynamic control by adjusting the power-off sequence based on real-time voltage conditions. Rather than using fixed timing for all power sources, the system dynamically determines when to start power-off for each group based on the voltage levels of previous groups, enabling adaptive control that balances reliability and responsiveness.
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
This approach enhances the responsiveness and reaction speed of semiconductor devices by reducing the power-off time and maintaining stability, while preventing prolonged discharge times from capacitors.
Implementation Method 1
the amount of time to completely power-off the power sources may be delayed differently by an amount of charge charged in capacitors of the power sources
Data Source
AI summary
A semiconductor device and a power-off method of the semiconductor device, the semiconductor device including a first power source group including first and second power sources, a second power source group including a third power source and a power sequence controller. The power sequence controller performs power-on operations and power-off operations of the first to third power sources. The power sequence controller starts a power-off operation of the first power source group at a first time, and starts a power-off operation of the second power source group when the power voltage of the first power source group becomes a first voltage or when a first reference time has passed from the first time.