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439 Threads found on edaboard.com: Voltage Smps
This is also a kind of resistance. But when an electric current passes through it, its resistance drops. Thus the voltage drop does not occur. If you refer to it's datasheet,you will see that it is related to its resistance at 25 °(in this type 100ohm) and its size(D-9).
recently i build led board that works on 5v. and as simple i use 7805 for prototype.but what about higher amount of current? i have option for 5v-10_or_20amp smps. but i have already 12v with enough current how to regulate them?
I was common for old smps designs to require 5% minimum preload to get 0.1% load regulation error. your design seems to be lacking the dynamic range on current & voltage error sense to maintain low errorwith no load.
Hello, We always here how voltage rails supplying FPGA?s DSP?s and Microcontrollers should have really low ripple voltage on them -otherwise they are said to suffer corruption of their internal data and operation by noise. However, how true is this? Often, these sort of processors are supplied by an smps, which obviously has a (...)
Hello We are delivering several kW's of power to a very low voltage system (1.8V). The downstream smps is obviously an array of paralleled sync Buck converters. Due to the obviously very low duty cycle of these sync Bucks, the sync FET is ON for the majority of the time. Therefore, the efficiency of the entire system is being determined by the r
Hi Everyone, Have a great day. I am using a smps WITH min voltage of 110 V nominal voltage 230 V and Max voltage 265V. This smps having failure of TNY CAPACITOR AND RESISTOR. The Sch is attached with this ( RED marked components are failing continuously ). Pls help me to resolve this issue.
Connecting 2 smps in series at the input side has a risk associated with it, if any of the smps input power is less than other smps (imbalance in the input impedance in spite of connecting secondary in series due to mismatched efficiency), that smps will get subjected to a higher voltage on its input. Also (...)
Hello, We are designing a 20W smps which simply supplies 15V at 1A to an RF Phased array antenna circuit. (its for comms). Vin = 48V. We were wondering if it is overly extravagant to do this as an Half-Bridge LLC converter? Its just that the smps will be very close to the Comms signal processors and other sensitive circuitry, so we wondered sh
Hey Can anyone suggest me how to improve this PCB layout? The transformer is 12V and logic side is working at around 200kHz. The power side is at mains voltage and also works at around 200kHz. The two MOSFETs will be placed on heatsink. Please take a look: obrazki.elektr
Hello, The attached is two smps?s in parallel. They both feed into the same output which is voltage regulated. There is a single error amplifier which feeds the two controllers (one for each smps). There is a micro which senses the current supplied by each of the paralleled stages and then makes adjustments to each stage in order to (...)
I cant see any feedback in your circuit. Also, I am sure you know the 1u blocker cap Is only for voltage mode. (have you set the sg3525 up for voltage mode?) The resonance frequency of the 1uF and the transformer leakage must be well lower than the switching frequency. - - - Updated - - - I believe you shoul
Here is a 5Vout 7A current mode, ccm flyback. It runs off the DC bus after the mains rectifier, and since you indicate 220VAC mains, I made it for 195vac to 265vac The duty cycle at min vin has been made small so that there is a decent length of secondary conduction time to make irms sec small. But the duty cycle was not made so small that th
I have a 12V smps which I believe I can set it to output 5V with a in-built pot. Will it be best idea to do that ? or should I set it to output more voltage like 9V and use a voltage regulator ? Because it needs to run microcontroller and other logic ICs and few amps load. The reason I'm asking is there any condition in which (...)
Getting 6V with no load suggests a defective circuit, or a switcher that can't work without a load. Check in datasheet & application note. If the circuit maintains 5V above a certain load current , it's probably the second case. The "24V" node is half-regulated and won't meet an exact output voltage without additional post regulator. Either stay
Use TL431 or similar secondary voltage regulator instead of Z-diode.
Hello, Here is two identical Full Bridge smps simulations in the free LTspice one has leakage inductance in the transformer, the other has perfect coupling (no leakage inductance). Notice how the one with leakage inductance has far less severe reverse recovery of the secondary diode. (attached are waveforms of secondary diode voltage (green) and
The effective gate charge that must be delivered by the gate transformer will considerably increase when the supply voltage is turned on. In addition, transformer inter-winding capacitance can have an effect. The first (no supply) waveform already suggests that the driver circuit is much too weak. It takes several microseconds to charge the gate
Yes you can simulate that to demo the point. Those diodes aren?t necessarily only for parallel smps, they can be used with a single smps. Its just that when an smps goes into no-load, its error amplifier tends to rail low?..the error voltage just plummets all the way down to the rail?..this is a problem when it is (...)
Presumedly the smps won't run with 24 V bus voltage, a typical wide range circuit has an undervoltage lockout threshold of 80 - 100 V. It may be possible to perform some functional tests with lower input voltage, bypassing the UVLO and startup circuit. But only at small fraction of rated output. Standard equipment for (...)
As a general rule switching power supplies have the - terminal referenced to earth ground. That's definitely not true for general purpose smps. The maximum output common mode voltage against PE is of course restricted, but surely no problem for 2 x 24V series connection. For the linked Astrodyne smps output isolation strength is e.g
You must find out why your hydro electric is upsetting the smpss. Is the voltage wrong or the frequency wrong. I have come across industrial size (250kW) maintained supplies which do not recognise the incoming mains if its more then 1% off frequency. Frank
Here is how smps controls its output voltage (this is in current mode control). Download free ltspice and run this, and you see the regulation components in the flesh. Ok it?s a flyback converter but the feedback circuitry is generally the same for the boost
you don't need "bleeder" ..voltage is too low at output to be dangerous, in any case, the leakage current of the electrolytics will bleed it down, - - - Updated - - - Hello, That?s a lot of secondaries that you?ve got there, and are you sure that the ee25 bobbin is actually deep enough to be able to ta
whatever value keeps the voltage at the mid point within say 1% of the nominal. Also, ensure no overly high ripple current in them.
firs of all do you think it's okay to feed two transformers from a single two switch half bridge ? given that the mosfets or IGBT's are powerful enough for the job? i could increase the startup capacitor on the SG3525, though even with this one the starting up is slow enough for me to see the voltage rise gradually over a sec or two on a simple
I am a beginning electronics hobbyist and I have never designed electronics. However, I'm somewhat familiar with power electronics from my work. I tell this that you can put my writing to proper context. Thanks, when I worked at an amplifier company, everybody was going on about igbts that can replace mofets, in 300w+ smps,
Reminds me of the adapters that come with a Universal Laptop charger coaxial plugs with a multi-wire interface. One of the wires to the smps charger was voltage sense and Gnd sense to regulate voltage at point of entry for loss in the wires.(remote sense) I modified the cable so I could adjust the output of the 19.2V 65W supply with pot, (...)
Hi, I can't believe.. What voltage rating are the bulbs? Klaus
To eliminate saturation laminate steel caused by sag in voltage or unexpected dropouts, there are solutions for large power transformers but not generally tiny ones. DC and low frequency, magnetic devices are current-controlled. At the smps switching frequency, they are voltage driven. Core limitations -saturation and losses -put (...)
Ropt should be connected to d1 cathode really. Rc is too big value at 1.6megohms - - - Updated - - - These are often due to tripping some protection mechanism in the controller. Eg UVLO, output overload, overvoltage on bias coil etc
Not enough drive current for Q8 to fan. Use a 1V Nch "logic level" Fet <<100mOhm. and consider Thermistor on hot spot to regulate bias a fan speed with injected triangle wave to get PWM. V CE(sat) Collector-Emitter Saturation voltage (I C =500mAdc, I B =50mAdc) Vce(sat) = 0.75Vmax Note : Ic/Ib=10 is common switch configuration, unless special
Yea right but i couldnt find suitable resistor as shunt. Since there is a 1R 1W resistor as the lowest value. But as 5W, there is 0.1R. I used two 0.1R in parallel. I live in Turkey and its not easy to get suitable components for projects. Can you not make resistor with a small copper wire jumper and a fuse. eve
I wonder which gate driver ICs you suggest for a buck converter with NMOSFET? TC4427 e.g. won't do. The isolated Infineon driver, yes, but only with a separate driver power supply. It must be a bootstrap driver to generate a gate voltage above Vin. And it needs an auxilary oscillator to charge the bootstrap capacitor if the output is not sw
The topology is LLC converter. It's variable voltage conversion factor relies on varying the switching frequency (or tuning the resonant circuit, which is obviously not possible with this circuit). It's effectively impossible that circuit works with 100 kHz fixed switching frequency.
The zener clips the + base drive pulse to bypass the base current and drain the 0.004 cap to reduce the output voltage. Raising the Zener voltage increases the duration of pulse and saturate the core more.
if i supply the opamp by the output voltage i inject many noise to my OPAMP. This trick can smooth the supply to your opamp. Install a resistor and extra smoothing 2) the o
The np/ns of the present design is that of a typical wide range off-mains smps. It's expected to work over a e.g. 90 - 240 or whatsoever input voltage range. I must confess that I don't understand what's the problem presently discussed in this thread. You have initially asked about snubber power dissipation, and it seems to me that the calculati
Hi there, I need some advice and guidance. I have this design specifications for the almighty smps :( 1)Input voltage : 24V-270V AC/DC (Universal Range) 2)Power Rating : 20W 3)Output voltage : 20VDC 4)Output Current : 1 - 2A 5) Isolated Add 1) I have troubles with this specification. Mainly ICs used in AC/DC converter (...)
There are at least two reasons why the transformer inductance matters, and I believe you know it. - D*Vin presumes that the inverter output would be zero during high-impedance phase, but that's not the case. Instead the stored inductor energy is driving the output in this phase - the ratio of input to output voltage is not exactly np/ns. You
THe ground shield is normally connected to power ground pin, but in situations where ground faults or high return DC currents cause offset voltage or injected noise into the common mode ground, designers may choose different methods of grounding for special situations. EMC is a two way situation for smps ingress with switching frequency nois
Thanks, yes i saw that..on page 5 of the datasheet it does indeed say "2mA"....However, the minimum pull-up resistance to the VREF is 3kohms...and the reference voltage is 3.9V in such a case, the opto would have to drop (3.9-0.8) = 3.1V across the 3K internal pullup, so that?s a opto transistor current of 3.1/3000 = 1.3mA ,
I see your point, but isnt 418v a bit near the 450V "common" voltage of the electrolytics at the output of the you know, pfc's are slow and if suddenly no-loaded, the vout could go above 450V. Our transient protection is via a MOV which is after the emi filter, and just before the diode bridge. We put it there because we want it to las
Hello all, I would like to vary the output voltage for my buck converter by a vary between 0 to 3.3V V_HV vary between 0 to 100V Can you help me how calculate the relation between V_DAC and V_HV :bang: How i calculate R1, R2, R3 :?: 117186 Thank you
Hi everyone. i have an oven with an electronic board that not working this oven have three electronic boards. 1) power supply 2) power (with relais) 3) control (with buttons and display) what does not work is the power supply. in input there is 220 vac but in output there is not 9.5 vdc. i tryed to replace an
Neutral ( near ground ) has nothing to do with an isolated output, nor does a resistive load. But best test method is active load test with MOSFET bank and control voltage with current sense and step load tests, cross load regulation etc., water cooled. or external dummy heater load resistors ( ceramic heaters are cheap.) or use Nicrhome wire in
A better Bang for the Buck (intended pun) is to design a low voltage drop linear regulator after the buck smps which maintains the constant low voltage drop, while the linear regulator minimizes the ripple and has the benefit of current limit control down zero with wide BW ripple rejection and low step-load regulation error. In the old days (...)
Do you plan to connect or disconnect heavy loads from the secondaries? This will affect output voltage at the other secondaries, even if it is for a moment. It is an issue you need to factor into your calculations for voltage levels and how to regulate them.
A PV is essentially a lossy current source that has a zener like open circuit voltage, Voc that declines slightly with lower solar input. The maximum power point is approximately 80+/-5% of Voc when the VI product has a shallow peak in power about this centre. You can hunt for this peak using MPPT regulated current sinking smps or approximate it
Hello, Pages 14 and 15 of the NCP1217 PWM controller datasheet show that PWM controllers with an internal high voltage startup regulator have a definite chance of destroying themselves with destructive latch-up at power down. The NCP1217 datasheet shows how to add external components in order to prevent this from happening. (Eg with a flybac
Yes its possible. I have used an MCU as PWM regulator with voltage and current feedback loops and other interface as well. If you do it right you might be able to increase the overall efficiency. ATMEGA is relatively more expensive than other MCUs I used. Microchip's PIC16F18xx series can be considered and if are able you can use NXP's LPC11xx whic