Power Supply Controller Dynamic Threshold Overcurrent Protection
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Solution Overview
Problem
Existing power supply controllers with self-protection functions face delays in detecting abnormal overcurrents, particularly during the transition phase of a power MOSFET from being turned on to reaching a stable state, leading to potential overheating and increased power loss due to a fixed threshold setting that may not accurately detect short-circuits immediately.
Innovation Solution
A power supply controller configuration that includes a current detecting element, a voltage generator circuit, an anomaly detecting circuit, and a protection circuit, which dynamically adjusts the threshold voltage based on the output voltage to prevent false protection operations and quickly detect abnormal currents, featuring a blocking circuit to inhibit protection during surge voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a constant threshold is used to detect abnormal overcurrent, then the protection function is simple to implement, but detection is delayed during the transition phase of the power MOSFET
Solution Approach 1:
The patent applies dynamics by making the threshold current dynamic rather than constant. The threshold current is adjusted based on the output voltage of the power MOSFET, allowing it to adapt to different operating phases. During the transition phase when output voltage is low, the threshold is lowered to enable immediate detection of short-circuit currents, while during normal operation the threshold returns to its standard level.
Solution Approach 2:
The patent changes the parameter of threshold current based on the output voltage of the power MOSFET. By correlating the threshold with the output voltage, the system can detect abnormal currents at different stages of operation. When the output voltage is below a reference level, the threshold current is set to a lower value to detect short-circuits during the transition phase.
2Reliability
If the threshold is set high enough to detect abnormal currents after stable state, then false detection is avoided, but short-circuits occurring during transition phase cannot be detected timely
Solution Approach 1:
The threshold current dynamically adapts to the output voltage level. When the output voltage is low (during transition phase), the threshold is automatically lowered to detect short-circuit currents that would otherwise be missed. When the output voltage returns to normal levels, the threshold returns to its higher setting to avoid false detections during stable operation.
Solution Approach 2:
The patent changes the threshold current parameter based on the output voltage condition. A voltage comparison circuit determines whether the output voltage is below a reference level, and based on this comparison, the threshold current is adjusted accordingly. This allows the system to maintain high measurement precision for abnormal current detection across different operating phases.
3Device complexity
If a fixed threshold is used for overcurrent protection, then the control logic is simple, but power loss increases during the transition phase due to delayed protection
Solution Approach 1:
The patent changes the threshold current parameter based on the output voltage to reduce power loss during the transition phase. By lowering the threshold when the output voltage is low, the system can detect and respond to short-circuit currents more quickly, reducing the duration of high power loss conditions.
Solution Approach 2:
The dynamic adjustment of threshold current based on output voltage allows the protection system to respond more effectively during the transition phase when power loss is most critical. The system maintains simple control logic while adapting the threshold to match the operational phase, minimizing energy loss during vulnerable periods.
Data Source
AI summary
One aspect of the present invention is directed to a power supply controller that includes a switching element disposed between a power source and a load, a current detecting element connected to the switching element and capable of outputting a detection signal in the form of a load current to the switching element, a voltage generator circuit capable of supplying an output voltage between the switching element and the load, an anomaly detecting circuit capable of outputting an abnormal signal when the load current exceeds a threshold current such that the threshold current corresponds to the output voltage. The present invention can further include a protection circuit capable of performing a predetermined protection operation based on the abnormal signal, a control circuit capable of receiving an on signal and an off signal, wherein the control circuit turns on the switching element when receiving the on signal and turns off the switching element when receiving the off signal, and a blocking circuit capable of blocking the predetermined protection operation when the off signal is received.