Search Engine

481 Threads found on Voltage Smps
Undervoltage detection isn't dimensioned for 85V minimal input, review the datasheet. Could be a problem if your input voltage is 120 VAC. 150V zener diode may be inappropriate depending on the transformer windings ratio.
HI I am designing FB-PS ZVS step-down converter using UC3875 controller. Actually i am beginner in field of smps technology but i have already created full bridge converter on base of UC3875 but without voltage feedback. I took example from UC3875 application note, picture
HI I am designing FB-PS ZVS step-down converter using UC3875 controller. Actually i am beginner in field of smps technology but i have already created full bridge converter on base of UC3875 but without voltage feedback. I took example from UC3875 application note, picture
Converting to three phase for 230/400V supply means to increase the nominal DC bus voltage from 325 to 560 V (+ overvoltage margin) for a simple (non-PFC) smps.
Obtaining real power (watts) information from a three phase source is not a trivial task. You have to perform a vector multiplication for the current and voltage of each phase, and add them together. Use a dedicated chip like the many offerings Analog Devices has. These can be then interfaced digitally, with a suitable isolation coupler, to
Hi all, This is Mohan, Actually i tried to measure input current of smps(3 phase input), to make smps automation circuit,we have used a 1 ohm resistor to the the series of all the three phases of smps ,normally when i measure in multimeter i saw 40mA at the smps input when i measure(voltage) across the 1 (...)
Hi, I am working on a project related to smps but now i am confused regarding the design of the half bridge converter which i am using after the pfc circuit(which is a dc dc converter called zeta).I have referred many designs and found that while designing the primary turns nominal voltage is considered in the design equation. Since i am using a p
Determine the load wire resistance and estimate the voltage drop. Consider if the uncompensated drop can be tolerated, possibly adjust the smps output voltage to increase the voltage to achieve 5V at the load under normal conditions. 5V/30A without separate sense wires is quite usual.
I'm in the process of designing and building an offline high power smps with constant current/voltage, to be specific it is going to be a 400KHz TL494 based half bridge with a 200-240VAC max 7,85A input and 50V max 20A output. I'm doing this with the hopes of eventually adding microcontroller based digital control to it to finely set the output vol
Hi, there are many different smps techniques. But for most of them the folowing is true: Example: Let´s say it is a 100kHz DCM flyback smps, input voltage 320V DC, inductor primary inductance of 2mH, output: 12V, 1A 12V, 1A means 12W. 100kHz means 10us cycle time Now calculate the energy that the load draws within one cycle: 12V x 1A x (...)
Pages 8 and 12 of the FAN6300A datasheet explain that the primary peak current limit of the FAN6300A flyback controller reduces as the primary DC bus voltage increases. This is said to be done by the FAN6300A sensing the auxiliary coil voltage (via a potential divider) when the FET is ON. However, we had a Flyback (smps) power supply (...)
Hi, For the varistor, it needs to be selected to have a trigger voltage above the required load/smps voltage and at or below the required clamping voltage, the current ratings are usually higher than 250mA. Try browsing t
You could do one of the last two options to get the same filtering effect as with one 400V 22 uF capacitor. In the last two options, the capacitor voltage rating is 200 V each. The resistors over the caps just balance the voltage equally over each capacitor.
My guess would be that it uses an SG3525 (or similar PWM chip) and drives 2 MOSFETs in push-pull configuration. So the transformer would be center-tapped on the low voltage side. The high voltage side has the voltages marked on the board. Hard to tell if it has feedback or not without seeing if there are components on the under side of the (...)
Hello, The attached is the mains input voltage and current waveforms of a 67W, Offline Flyback converter that has no big smoothing capacitor after its mains rectifier. The flyback operates in constant off time mode. As you can see the power factor is overall better than an offline smps using a big smoothing capacitor after the mains rectifier. I
Good advice from schmitt trigger, also you transformer calculations have a problem. A half bridge transformer only see's 1/2 of the DC input voltage so your 325 vdc in the formula should be is 1/2 of that. Also the constant in the formula should be 4 not 8. Npri = (162 * 10^8) / 4 * 50000 * 1500 * 1.75) = 30.9 turns By dumb luck your two mistak
I will use the SCR like a diode between the capacitors and the load. Sounds erroneous. A SCR can't switch-off DC current, at least not without a second commutating switch. The problem of instantaneous current limiting refers to inherent limitations of a switched mode power supply in achieving current and voltage dynamic. Most mo
There are good reasons why any three-phase power supply on the market doesn't use neutral... Otherwise you need to measure phase-to-neutral voltage and define an acceptance window.
I had designed a power supply using PI expert.I designed the same using the PI expert tool for 5V, 0.8 A configuration. I have attached the Schematic from PI expert, Eagle Schematic of the same, PCB design. Only difference in circuit made is the ceramic capacitor attached to BP/M pin is 0.1uf instead of 10uf I got the output as 5V at No L
Hello, I have designed an smps with dual outputs of 5Vdc and 12Vdc and i have to prepare a datasheet for that smps. For that, i need to specify one parameter for minimum and maximum AC input voltage by which smps can function and give correct outputs. i have tested maximum input voltage of 440Vac (...)
5V well with 1 mA load, when I connect the 50 Ohm resistor Vout falls to 2.5V. ... regulated Vout falls by half. ?? A typical cause is oscillations which travel the range between supply rails. Hence their average voltage is V/2. Or perhaps the frequency is too fast for the device to handle, so that the waveform hovers
The schematic in post #1 has wrong polarity of coil, diode and output capacitor for the channels intended to give negative voltage.
Hi, Having problems with load regulation of SEPIC. It's on a breadboard, but doubt that is the cause of the problem, may be compensation, or other, looking for tips to troubleshoot, and ask question/help about compensation, as I'm finding parts of that very hard to understand. Line regulation appears acceptable, for +4.8V/+5.5V/+8.5V in outp
Hi I want to design smps with LCC topology with the below specification Vin=650 volts Vout=1000 volts Iout = 20 amp frequency=50 khz output ripple voltage=1 volts I want to calculate the capacitance of output capacitor. I know the below formula: C = / Vr C in Farad I in Ampere f in Hz Vr in Volts
If you have a (more or less) constant load, you can make a simple linear power supply. If you want to avoid a bulky transformer, go for a smps design. If you want a tight regulation of the voltage, you need to consider a regulated supply.
Dear All, I want design smps with battery back up for long time. But my charging current is very low approx. 2Amp but i want to increase it. I want design the system with following specifications: Output voltage : 12-15VDC Load current : 4Amp. Battery charging current : 6Amp. With overload protection Can anybody help me?
Hi, Your description is not clear. * what is your input voltage range? * what is your output voltage (range)? * what is your (output) current (range)? Generally: I_in = I_out * U_out / ( U_in * efficiency) Klaus
Do as per FlapJack. We measure noise with 50 ohms system. Oscilloscope : 50 Ohms input, DC coupled, Offset adjusted. lower voltage/division capacity like 2mV or 3mV/div, try with 20 Mhz BW limit for better performance., Cable : RG174 cable(rf174-04sp3-04sp3-2000 these cables are avbl fom samtec) has very small core, useful in soldering directly acr
Maybe there is a problem on the feedback line( at the low voltage between optoccupier and tl431
I was trying to make a circuit of DC voltage booster131983 It showa a maximum current of 400 milli amp going through the collector of bd136 while in reality it should have gone to Killo Amperes considering that inductor series resistance in proteus is just 0.00002 ohms
?surely the above thread is incorrect?..smps output ripple should best be measured with a x10 scope probe, and not a piece of coaxial cable which will be a 1:1 probe and will overly capacitively load the high frequency bit of the measured value? All that is needed is to remove the ?tail? at the end of
Does the smps have an adjustable output voltage? (24V could be very high for 5V, unless your smps can output 5V.) An easy way of generating a negative voltage is to use a (cheap) charge pump, like the 7660, but this device only outputs the voltage that goes in, e.g. +5 > -5, etc. Or you could use a (...)
Your secondaries have the same number of turns (9T). Theory says they produce the same voltage. However your specs say you want three different voltages. Does the transformer have internal construction which provides this? Or did you intend to add regulation?
Hello, For the VTM48? power module, what is the tolerance on the PC pin voltage during fault? The VTM48? datasheet, on page 3 says that PC pin goes to ?2.5V? during fault. But what is the tolerance on this voltage? VTM48? power module datasheet
This concerns the attached schematic of a 48V to 1V5 smps which uses Vicor power modules. Do you agree that the Error Amplifier small signal transfer function should feature a ?divide by 24? factor? -And that this must be done so as to take into account the fact that the output voltage is sensed at the 1V5 rail rather than from the intermediate 36
Is it asking too much to demand a complete specification, including an input voltage range? Either if the output current is 100 or 600 A, you would always prefer a multi-phase converter instead of a single-phase switcher with all switch transistors connected in parallel.
My plan is to make a charge controller to auto charge a 12v Lead Acid battery. Here is the idea - 1. Power supply will be adjusted to deliver a safe voltage above 12 volt. Say 14v. Note that ampare rating of the power supply is 20A (safe for a 120AH battery) 2. Power supply will be connected to the battery terminals and the charging will be
Most audio amps do not have a regulated power supply voltage. They simply use a large enough mains transformer, rectifiers and a large filter capacitor. The DC voltage normally rises a little when the amplifier plays quietly or idles then drops a little at full output power. The little voltage fluctuations are ignored by the circuit.
Hi, i have 15V and i would to have 5V, i dont want to do it with switching power supply because of its noises. if i do it with voltage regulator; Power Loss = (15V-5V).1A = 10W. Power lost is so much. Any ideas how can i do it? thank you best regards
Hello, We are doing a 48V to 1V5 smps using a vicor PRM48 power module feeding down to a VTM48 vicor ?electronic transformer?. (the intermediate voltage is 36V). On page 21 of the PRM48 datasheet, the output voltage of the PRM48 is shown to slowly ramp up at startup?.also, during this startup, the PRM48 output current is being held very (...)
Hello The attached schematic varies the reference voltage shown from 0V to 1v5. (In the actual circuit it will be the variable reference to the error amplifier of an smps..thus giving a soft start by slowly incrementing the reference node voltage). Do you have any ?less component count? ways of doing this? I need to keep the LT1634 (...)
Hello This smps module appears to have a settable output voltage via its ?REF? pin which enables the user to set a voltage at the error amplifier reference input. However, when "Adaptive loop? mode is set, the datasheet says not to use the ?REF? pin. Why is this? Why can we not use the REF pin to set the Vout? MPRM48NH480M250A00 (...)
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