Grouped Power Rail Shutdown for Stable 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 shutdowns and reduced responsiveness due to voltage level decreases and capacitor discharge characteristics, resulting in power-off times that are significantly longer than power-on times.
Innovation Solution
A semiconductor device with a power sequence controller that initiates power-off operations in a cascading manner, starting with one power source group and progressing to subsequent groups based on voltage levels or reference times, allowing for controlled and efficient power-down sequences.
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 stably controlled, but the power-off time becomes slower than the power-on time by dozens to several hundred times
Solution Approach 1:
The power sources are divided into multiple groups, and the power-off operation is performed sequentially for each group rather than controlling all power sources individually as in power-on operation. This segmentation allows the system to maintain stability while reducing total power-off time.
Solution Approach 2:
The power-off control method dynamically adjusts the control sequence based on the operational state. During power-off, instead of following the static power-on sequence, the system transitions power sources from operational state to standby state more efficiently, adapting the control strategy to the specific phase.
2Reliability
If individual power sources are controlled at fine levels during power-on, then inrush current is prevented and power is stably supplied, but it becomes difficult to control power sources at fine levels during power-off operation
Solution Approach 1:
Power sources are segmented into groups that can be controlled collectively during power-off operations. This grouping simplifies the control mechanism while maintaining adequate stability, as the segmented approach allows for manageable control units rather than individual source control.
Solution Approach 2:
The control parameters are changed based on the operational phase. During power-off, the system uses different control parameters compared to power-on, adjusting the level of control from fine-grained individual control to group-level control, making the operation easier while maintaining necessary stability.
3Loss of time
If voltage levels of power sources decrease due to discharge during power-off, then capacitors discharge at different rates, but this causes delayed shutdown and reduced responsiveness
Solution Approach 1:
The power-off control method dynamically monitors the state of power source groups and adjusts the shutdown sequence accordingly. When voltage levels decrease and capacitors begin discharging at different rates, the system adapts by controlling groups sequentially, ensuring faster shutdown while maintaining consistency through dynamic adjustment.
Solution Approach 2:
The system incorporates feedback mechanisms to monitor voltage levels and discharge rates of capacitors during power-off. Based on this feedback, the power sequence controller adjusts the shutdown timing and sequence for different power source groups, achieving both speed and consistency in the power-off process.
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.