Power Supply Controller Dynamic Threshold Adjustment
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Solution Overview
Problem
Power supply controllers face challenges in detecting overcurrent anomalies early while preventing inrush currents, leading to repeated shutoffs and delayed power supply to loads due to inappropriate threshold settings.
Innovation Solution
A threshold adjustment method that dynamically adjusts the overcurrent threshold based on time and detected current levels, allowing for an initial high threshold during power-on and reducing it once current is established, with additional mechanisms to prevent repeated shutoffs due to inrush currents and detect overcurrents accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the overcurrent threshold is set to a lower level to detect overcurrent anomalies early, then overcurrent detection sensitivity is improved, but the semiconductor switching element will repeatedly shut off due to inrush current during power-on
Solution Approach 1:
The patent applies dynamics by making the overcurrent threshold time-dependent. During the power-on period, a higher threshold is used to accommodate inrush current, and after the power-on period expires, the threshold transitions to a lower level for sensitive overcurrent detection. This dynamic threshold adjustment resolves the contradiction between early overcurrent detection and prevention of false shutdowns during startup.
Solution Approach 2:
The patent implements preliminary action by establishing a power-on period before normal operation begins. During this preliminary phase, the higher threshold prevents false shutdowns caused by inrush current. Once this preliminary phase completes, the system transitions to normal operation with the lower threshold for accurate overcurrent detection.
2Reliability
If the overcurrent threshold is set to a higher level to prevent shutoffs during inrush current, then power supply stability is improved, but overcurrent detection capability deteriorates
Solution Approach 1:
The patent resolves this contradiction by implementing a dynamic threshold that adapts to the operational phase. The threshold is higher during the power-on period to ensure stability and prevent false shutdowns, then automatically lowers after the power-on period to enable sensitive overcurrent detection during normal operation.
Solution Approach 2:
The patent segments the operational timeline into distinct phases: a power-on period with higher threshold for stability, and a normal operation period with lower threshold for detection sensitivity. This segmentation allows each phase to have optimized threshold settings appropriate to its characteristics.
3Reliability
If the semiconductor switching element shuts off repeatedly due to inrush current, then inrush current protection is achieved, but the control progress to power supply for load is delayed
Solution Approach 1:
The patent applies preliminary action by pre-defining a power-on period that anticipates the inrush current phenomenon. During this predetermined period, the higher threshold prevents false shutdowns, allowing the load to receive power without interruption. This eliminates the repeated shutdown/recovery cycle and accelerates the control progress to full power supply.
Solution Approach 2:
The dynamic threshold adjustment based on the power-on period timing ensures that the semiconductor element remains protected during startup while enabling continuous power supply to the load. The threshold automatically adapts to prevent shutdowns during the critical power-on phase.
Data Source
AI summary
An inrush current higher than a second anomaly threshold current ILfc passes through a power MOSFET 14, when a control signal S1 of low level is applied to a gate driver 28 so that the power MOSFET 14 and the like turn to a conductive state. A first forcing shutoff operation for the power MOSFET 14 is then prevented, because a first anomaly threshold current ILoc is set to an initial level higher than the inrush current. A fuse time counter 73 starts a count-up operation in response to the occurrence of the inrush current, and continues to increment its count value until a load current IL falls below the second anomaly threshold current ILfc. According to the count value, the first anomaly threshold current ILoc is decreased stepwise with time.