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412 Threads found on Voltage Smps
I have designed a fixed frequency flyback smps (5V, 1A) using STM's design studio using Viper17 series. I do not have much knowledge about smps practical issues. The supply is working fine ( with some voltage variation) on no-load but the voltage drops to half value on a load of as small as 10mA. I am unable to (...)
I have designed adjustable output voltage and curent smps having 500W output. I would like to share circuit schematic since there are many experienced people in smps and power electronics in this forum. Do you have any suggestion about this circuit ? or Do you see any critical fault ? This project may help to people who want to build a (...)
I am planning to design smps that has variable output voltage and current. Its voltage will change 0-50V and current will change 0-10A. 120251 Vout comes from output voltage up to 50V. Iout comes from output current up to 10A. Iout will be Rshunt x 10A. Rshunt is 0.05R, so Iout will be 0.5V as voltage. (...)
I got my simulation to work on multisim but would need to build the actual smps. The microcontroller I'm using is only capable of outputting 5V. I would need it to be 18V like it works at in my simulation. Is there a way to get the voltage up so it can drive the gate of my mosfet? I've thought about using a gate driver ic but don't know what to buy
Hello, We have had a 3kw offline (85-265VAC) battery charger made for us by a consultancy. They did not give us the schematic. The chargers are failing and we are wondering why. First of all we are trying to assess what topology it is. The schematic that we have determined so far, by using the DMM on the PCB is as in the pdf. However, when we
Recently I purchase a china made Rechargeable LED emergency light which contains 1 6V5Ah battery. Upon inspection I find that the circuit board contains an smps + a transistor switch to control the light. The smps it contains is exactly the same as this .
Hi FvM, Thank you for your answer. but i have a remark, if i supply the opamp by the output voltage i inject many noise to my OPAMP. 2) the output voltage vary = supply OPAMP very !! (and the offset of OPAMP change !!) 3) is it possible to use an other solution for driving this inverter without negative supply ? Thank's Paul
Here is my simulation, for comparison purposes. I certainly would not dispute your statements. You're correct that the snubbing network averages around 6W worth of heat I thought up another theory about
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 (...)
Hello, The following two LTspice simulations are almost exactly the same (both full bridge smps?s)?They have the same NP/NS value, but slightly different primary and secondary inductance values. Everything else is the same about these smps's. So why does the one with lower primary inductance have a higher output voltage? (316V (...)
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
Hello everyone, I need to check a multiple output smps for its voltage and current rating. The input for this smps is 380 volts 3 phase without neutral. and there there 7 isolated outputs. I need to test each output for its rated voltage and current. i heard resistive load wont work as the design does not have a neutral. (...)
Hello. I have for a while been designing a step-down dc/dc converter, I have no education to speak of nor experience and all I know I have learned online. That leaves me in many cases unable to use information I find, the following is not 100% serious but there seam to be a safe guard in place allover the application notes related to amongst ot
I want to make a Push Pull type DC-DC converter with multiple outputs for driving the gates of an inverter and also some control circuits. While bootstrap method is popular, it has it's limitations. All the people at our college use a large no of isolated power supplies to do this and I want to make the Power supply part compact and cheap. I am th
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
I think it will be better if you share more on what information is available with you - so that others can help you faster. One option is - if you are able to scope out the voltage @ diode in secondary or the current through the diode - all before the capacitor in secondary, you can measure the switching frequency.
You need to understand Ohm's Law and basic electricity to see how much current is used. The rated current of a power supply is the maximum current it is allowed to provide. It does not provide that much current all the time. Ohm's Law says that the current is the voltage divided by the resistance. You have a load that uses 600mA when the
Hello, Please can you confirm that when the primary FET switches off, the voltage across the leakage inductor, which resets the leakage inductor, is the (RCD clamp voltage) minus the (voltage referred from secondary to primary)? ....and if these two voltages were equal then there would be no voltage (...)
In case of doubt, a solid ground plane won't be bad. The LED driver circuit can't work. The IR-LEDs have only 1.2V forward voltage each, so a simple series resistor from 5V would be the appropriate way to supply it, or a buck converter if minimal power consumption is a must.
Feed the voltage across the current sense resistor to the IN+ of an opamp then adjust the opamp gain (using a pot) to get ~1V at its output for any specific charger output current (1 - 15A). The opamp output shoud be connected to the curent sense pin of UC3842.
Hello, We wish to scope the voltage across the output diode in our offline , isolated flyback smps. (to see how high the ringing voltage goes) Should we use a differential probe, or will it be accurate enough to simply connect the actual scope probe directly?
I want to know the maximum voltage and current output of a desktop computer power supply.
So it not going to be in very harsh conditions... Will have to re-read the spec to get pollution level If the board develops cracks you are going to be the unluckiest designer in the world.... because it would be the layer to layer clearances that would be affected and if you have high voltages then the design should be done so that cracks etc. do
NOT quite. He states how it is more useful to skip the frequency domain simulation and start with time domain simulation to optimize stability of overshoot. He points out how to stay in "current-mode" so that it becomes inherently stable. Use variables are input voltage and output step currents. Design choices depend on priorities, cost, per
What are you using it for. If just basic scoping low frequency signals then almost anything will do. If you want to depict ringing and peak drain voltage spikes in smps's then you will need high bandwidth. Beware some of the Far eastern ones where the save_waveform feature doesn't work on windows 8. Do you need sample and hold....if so, don't buy a
You can use an isolated gate driver like TLP2200. Problem in any case is that you need a low voltage supply for the gate driver. Usual solution in regular smps: Startup circuit is deriving the supply voltage from input DC voltage by a series resistor + Z-diode, in operation an auxilary transformer winding is supplying (...)
Full Bridge smps primary DC blocking capacitor...(capacitor in series with primary) Does any reader know of a book that explains ...... 1. Whather or not this capacitor is needed in voltage mode control? 2. Whether or not this capacitor is needed in Current mode control? 3. Whether or not this capacitor is needed in Current mode control
it means that you have an smps where as soon as the inductor current falls to zero, the driving voltage is again forced across the inductor and the inductor current begins to build up again. So the inductor current falls to zero , but does not languish other words, the inductor current is triangular and not trapezoidal, and there are n
I could not find the proper spec sheet for transformer which determine the power or voltage current rating of transformer. I also could not find the turns ratio. If u know the cross sectional area of input and output coils with their length, the resistance of coils can be found. Using these values u can determine the VA rating and with power factor
Hi all I have some stupid question about ac-dc conversion. As you already know, diode-bridge is connected to AC line and rectified voltage is go through flyback stage in case of flyback ac-dc smps. - AC Plug -> Diode bridge -> Flyback stage Then let me write a stupid question. How about below construction? - AC Plug -> transformer
Why don't yu try a Linear Adjustable Regulator just after this smps ?? You may design your smps ( for instance 85-270VAC )then you can connect a variable regulator then.. smpss work still rectified line voltage so DC.Flyback is a good choice..
i have a power supply in which driver ic is ICE3BR0665JF AND FB controlled by TL431. its a 18vdc,100w smps.i want to use it in project where i need 24v dc it suitable to use if yes how to change its output to 24.what about its performance. if any other circuit plz suggest its urgent
basically this inverter incorporates high frequency intermediate stage , however the output frequency is still 50/60 Hz, In this inverter , basicallly there are 2 stages , 1) DC-DC stage 2) DC-AC stage in first stage a lower voltage dc say 12V is converted to 311VDC now in second stage the 311VDC which is a peak value is converted into 220V
Dear Friends , I have a circuit which works as following : Mcu board : reads temperature via pt100 sensor , shows temp on lcd and it has to print the data on a thermal printer . Mcu board is working on linear power supply which powers voltage to pt100 circuit , mcu , lcd etc. The thermal printer requires 5V , 2A of current so i am using a pc
I've done googling...Majority telling only 3 important things must consider then it'll work: 1.) voltage 2.) Current 3.) Rds-on resistance Any opinions on this? Thanks. I agree with previous posts but would like to add the following concerns that ought to be checked. - If significantly lower RdsOn,
Feedback is more complicated in a boost converter than in a buck converter. One issue is that your desired Vref does not exist for the first few cycles. When you finally have your Vref, it cannot be applied directly to your control device, since it is outside the supply rails. It must be divided down. Vref (voltage regulation) is one type of feed
I want to control voltage (CV) and current (CC) using TSM103 at smps output. Please help me design calculation . I have to CV/CC at smps output having 54V and 1.4A.
hi , i have built a half bridge smps with pfc front end for 2 X 200W class - D . it works fine but the wave forms that i see is troubling me .... Can any one have a look and tell me if i am doing it wrong ..... the smps has a open voltage loop . wat is troubling me is primary waveform at 90% load the wave form should be flat during the dead (...)
If the turn ratio of the transformer is wrong and there are more turns in output coil than needed then it will produce higher voltage level in output. The feedback circuit will try to regulate it by reducing duty cycle and you will see a narrow pulse of PWM output especially when there is no load present. .
I think, the shown circuit has sufficient protection, even if the signal pins are connected first. What you can expect at the maximum is a few nF smps Y capacitor charged to the mains peak voltage which will discharge through the 6.2 k resistor. Stored energy is below 1 mJ, no problem for a 0603 resistor. The Z-diode will safely protect the MOSFET
Hi I need a inverter for a Mig/Mag machine wil wire feed, I have read this has to be a constant voltage source needed of 22/28 volts. So correct me if I wrong. the constant voltage source is a version of smps with voltage feedback to adjust voltage? wire feed speed take care of current. the Tig (...)
So I connected it between 9V 4.5A DC smps and external camera flash which requires 4xAA cells. To my surprise when flash is charging input current rises to 2.2A and voltage drops to about 2.5V. Is this normal?
I prefer the guru Keith Billings who has 50 yrs smps design experience and many books. The choke must not saturate during Ton and must have enough energy stored during Ton so the voltage does not sag during Toff. Th
I presume you used a design simulator such as WE's component selector which calculates all the losses. Since you did not provide any details on input /output voltage we cannot say for sure. e.g. Why 200kHz? why not 250k? What were your results? <150mW?