How it Works. The functioning of the adjustable current sensing module can be understood as given under: For circuits which may have a ground shutdown feature, the circuit using the NPN device could be employed as shown in figure on left. Here Rx is selected such that a potential difference of about 0.6V is developed when the amp consumption at 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 1: If the current could physically damage the diode or thin wire between the chip and outside pin. 2: If the current is more than the total power consumed from the 3.3V power supply (approx 100mA) then the excess current could also raise the 3.3V power to a higher voltage, which subjects the whole chip to higher voltage than it can handle. 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 Yes, everything must be within the limits of a CV or CC supply. In the example in my previous post with the 100 A PSU set to 12 V and a current limit of 1 A, you will have noticed that it operates EITHER in CV mode OR in CC mode, depending on the load. With too low a load, it cannot work in CC mode. With too high a load, it cannot work in CV mode. Figure 2 The PCB layout and components layout. NOTE: Because IC number is high price.You may use the LM317 and transistor, to expand the current demand. Click HERE >>> Best DC power supply 3Amp to adjust 1.2V-20V & 3V-6V-9V-12V add transistor 2N3055 parallel from 3A to 5A easily. Related: Dual 15V Power Supply Schematic With PCB, +15V -15V 1A 1-20V, 10A Adjustable DC Power Supply across the power-supply voltage for hold-up. If hubs are used, current limiting will definitely be required due to the unknown nature of the peripherals that will be plugged into the hub. The current limits can be implemented in two manners, one using discrete power devices with external control circuits, and the other with the switches Therefore in this variable power supply circuit using 2N3055 transistor, the transformer being a 0 - 40 V, the output becomes variable right from 0.6 to 40 volts maximum, that's very handy indeed. For implementing the current control feature, T3 along with P1, R5 and R4 are involved. The value of R4 is specifically becomes responsible for Applications of Current Limiting Circuit. Current limiting circuits are applicable in electronic circuits to restrict the flow of current through a load. They have various applications, including the following: Power Supplies: Power supply circuits often use current limiting circuits to safeguard their components from overcurrent situations power supply - Current limiting using P-CH MOSFET - Electrical Engineering Stack Exchange. Current limiting using P-CH MOSFET. Ask Question. Asked 6 years, 7 months ago. Modified 6 years, 3 months ago. Viewed 8k times. 1. I am currently building variable voltage/variable current (lab) power supply out of an ATX switching power supply. In simple terms there is no difference between constant current and current limit. If you take a "constant current" supply and leave the terminals open circuit, the current will be zero. Therefore the current is not constant. It is variable between zero and the desired set value. In the same way, the power supply is not "constant voltage" either. 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 Simple Current Limit Circuit: . 5V. GND. R2. +12V. Q1 2N3904. 1K Q2. 2N3904. R1. 14. GND. This circuit will limit the current through the load to about 50ma. As before when the input to the base resistor is 5V Q1 turns on and current flows through the load. When the input is low Q1 is off and no current flows through the load. Precision High Side Power Supply Current Sense (Figure 9) Additionally, the current limit of the amplifier can be adjusted to control the torque and stall current of the motor.Motor Speed Control (Figure 114) This uses an LT1970 power amplifier as a linear driver of a DC motor with speed control. The ability to source and sink the same 1. If you are trying to limit current why would you put an additional resistor in parallel with the load. All that does is consume more current from the 12V supply and creates needless heat. Just connect your load to the 12V supply by itself and be done with it. If your load is indeed 40 ohms then the net current draw by the load will be 300mA. bAjd2.

power supply with current limit