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70 Threads found on Current Mode Loop
Undervoltage lockout being tickled by weak mains, poor socket connection or a PFC front end problem? Thermal protection toggling due to a die or board level heat issue? Control loop instability? Noise issue w/ current mode control at low duty cycles is often a problem, with the turnoff edge coming close to turnon the switch "ringing (...)
Hello, The LTspice simulation of a 28vin to 1V5 out, 20A out, Dual Buck converter (each buck switches at 200khz and is in CCM, current mode) shows a crossover frequency of 14000 Hertz and phase margin of 63 degrees. The excel calculation of this circuit (also attached), gives it as 9600Hz for crossover, and 53 degrees for phase margin. ?So slig
Most likely you have a large common mode noise interfering with a differential current source, sense. Try a large CM balun or ferrite sleeve or twin coupled choke to the twisted pair to raise CM impedance and thus CMRR but keep DM impedance relatively low compared to Zc(f) If that fails, reduce area of loop with a smaller gap . water has (...)
Every pin voltage should either be GND (0 ... 0.3V) or VCC (VCC - 0.3V .... VCC). Any other value shows either activity or a floating signal. Both increases power down current. It's a bit different with 8051 processors. Port 1 - 3 are open drain with weak pull-ups, the outputs must be programmed to '1' (the power-up state) and not
Hello The attached is a power supply involving eight current mode (CCM) bucks all in parallel, driving into the same load. Its easy to get the Feedback loop bode plots (& calculate gain and phase margin and crossover) for one buck supplying into one load, but how is it done for eight in parallel? Vin=28v vout = 1v5 iout = 136.8A (...)
HELLO!!!!! I want connect two microsources namely (microturbine,and DC SOURCES) with different capacities ( P1=35kW,P2=20KW) but i am using droop controller with PI.And every microsources has voltage loop ,current loop and power loop . Anyone who knows a method which i can use for achieving a good way of (...)
Hello, In a current mode flyback, compensated with a type 2 error amplifier, it is a fact that the error amplifier's high frequency pole should always be at a lower frequency than the frequency of the power stage ESR in order to assure you avoid instability Is this true? ie, ensuring the above won't assure stability but is a good and
Hi, I want to implement a digital controller for a switch mode power supply in Orcad pspice. The controller will take voltages and current values as inputs and create the control signal using intelligent algorithms (state machines, digital control techniques etc). Therefore I need a block that runs a code for processing these values (ie. C
The ZXLD1370 LED driver datasheet says that it regulates its switching frequency to 400KHz (bottom of page 5 of datasheet) However, page 14 of the datasheet states the following??.. **The control loop also regulates the switching frequency by varying the level of hysteresis (the ripple in the inductor current). The hysteresis has a d
For a Full Bridge SMPS in current mode, as opposed to Voltage mode, we can say that with current mode, we no longer suffer the double pole of the output LC stage, because current mode control cancels out one of these poles, meaning that we can more easily compensate the (...)
This is the case with regular sampling PWM, but for natural sampling PWM the phase response is very small (and can lead or lag, depending on specific conditions). I don't think that the difference matters in this relation. The sampling time can be considered as fixed for a small signal disturbance, also with natural sampling. Yo
Hi everyone, I've been trying to implement a compensated closed-loop current mode(CM) controlled boost converter using the SIMPLIS engine. However, I am having convergence issues with the simulator. Here are the converter specs I followed: Vi = 12V, Vo=18V, Io=1A, fs=100khz. To have a solid understanding of CM, I used primitive (...)
The following is a flyback with vin = 250V, VOUT = 30V, pout=22.5w, fsw=97khz, CCM, current mode. The only way to measure an effective feedback loop gain/phase plot is to put the two opamp buffers (U3 and U2) either side of the feedback loop injection resistor, R7. Do you agree? (schematic attached) The ?standard? (...)
Hello, I have the small signal feedback loop transfer function for a CCM, current mode, buckboost. (Basso book page 232,fig 2A-22) I need to adjust it so that it can be used for a flyback... -So does vout become vout*.? -does Cout become Cout*.? -does Rout become Rout.? -does Cout's ESR become ESR/[(Ns/Np)^
Presume you are transiting to DCM by decreasing the load current. Modulator gain increases with decreasing current.
Hello Why does the SEPIC converter (5V-15V) with a SEPIC capacitor value of 10uF go unstable? The exact same sepic converter, but using a 33uF Sepic capacitor is perfectly stable. Why is the one with the 10uF capacitor unstable? Also, a sepic converter which steps down from 15V to 5V and uses a 10uF capacitor is perfectly stable.
Hello, The following sepic led driver regulates its own input current. spec: vin= 5 to 8v vout = 5 to 40v pout = 1 to 5w has overvoltage protection. Coupled sepic inductor. F(sw) = 30KHz - 125KHz Its peak current mode, but the main negative feedback loop is closed around the input (...)
Hello guys, I have a project in electronic which is to measure the current passing through the winding of a bipolar stepper motor, design an analog circuit and then convert the output value to this circuit with the help of a microcontroller which will have theses input configured in ADC Conversion, I just want to know if you have an idea og
hi I am doing my course project on clock and data recovery. In that in phase aquisition loop phase detector is implemented by current mode logic.The problem is when i gave phase detector error output signal to v-i converter(Differential amplifier is one of stage used for voltage to cuurent converter) it is switching in only one side (...)
I have to calculate 1. current in each branch, 2. voltameter result 3. electromotive force (EMS) mode and 4. power bilance. And need to use four methods: Node Voltage Analysis (Node potential method) Superposition Method loop current Analysis Kirchoff's Rules Analysis I hope you can rede something or give me (...)