In your example, the current limit is set to turn on when the voltage on Rsens is enough to turn on Q2, or about 0.7 volts. When shorted, your system does not shut down but continues to deliver this current into your short. switch-mode-power-supply; dc-dc-converter; protection; or ask your own question. The Overflow Blog Can GenAI 10X The current sense signal is an essential part of a current-mode switch mode power supply design; it is used to regulate the output and also provides overcurrent protection. Figure 1 shows the current sensing circuit for an LTC3855 synchronous switching mode step-down power supply. The LTC3855 is a current-mode control device with cycle-by-cycle The LTC3855 is a current-mode control device with cycle-by-cycle current limiting. The sense resistor RS monitors the current. Figure 1: The switch mode power supply current sense resistor (RS). Figure 2 shows a scope image of the inductor current for two cases: in one case, with a load that the inductor current is capable of driving (red line The voltage and current controls on a bench power supply both function as limits, not settings. If you want to supply a specific voltage to the load, adjust the voltage control to that voltage. The power supply will deliver that voltage unless the output current goes above the setting of the current limit control, in which case it will reduce 1) Limit inrush current. 2) Help clean up the 12V input. I have done some simulations. Cap: 660uF with 130mOhms ESR. Inductor: 4.7uH with 37mOhm resistance. 12V DC input with 1V/uS rise time. (Just guessing on that one since I don't have control over what the source is. This gives me: This gives a peak current of 62Amps. Dan Maloney. June 5, 2023. Here at Hackaday we really like to feature projects that push the limits of what's possible, or ones that feature some new and exciting technology that nobody has If one has enough space, and is operating at low enough power levels, that having the supply draw the maximum current from its source transform and dissipate all the power as heat would not pose a problem, a transformer, a regulator, some caps, a handful of resistors and two LM317 regulators would suffice [without current limiting one would it is easier for an over-current event to occur. If the power supply starts to hiccup once there is an over-current, it Vo A I 1/3IMAX IMAX A B C Vo I IMAX Figure 1: I-V curve for a power supply with maximum current limiting Figure 2: I-V curve of a power supply with current foldback Current rating of the over current protection device must be ≤ 5 A. Maximum VA must be ≤ 250. Maximum marked output power rating of 5 A * Vmax. Maximum marked output current rating of 5 A. Dc voltages > 20 Vdc and ≤ 60 Vdc and substantially sinusoidal ac voltages > 20 VACrms and ≤ 30 VACrms. Power supply class is extensible, and allows to define drivers own attributes. The core attribute set is subject to the standard Linux evolution (i.e. if it will be found that some attribute is applicable to many power supply types or their drivers, it can be added to the core set). It also integrates with LED framework, for the purpose of nHbHau.