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407 Threads found on edaboard.com: Voltage Smps
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 (...)
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
There is a pair of resisters still burnt on the board in the photo. Melexis is a good company for MLX chips but no longer seem to offer this or any smps parts on their website. Normally it goes like this... an unexpected over voltage saturates the coil (at f) which reduces the impedance from 50% to <10% of original , which blows everything in its
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
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
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
Apparently a defective core voltage regulator. Probably total loss. The CPU chip may be damaged too.
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.
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.
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?
TVS will not fix your problem. Preloading your smps for 5% may reduce overshoot. Improving design Phase margin may improve it more. I think you have a measurement error as the LED current would be nonlinear and ringing would NOT be sinusoidal at this voltage >60V. ....Reason is the LED string will probably have a lower ESR than the 500W rated
I presume you have an idea about the block diagram of the inverter. To use the ferrite transformer for battery charging, you need to feed the high voltage winding of the transformer with a 50 kHz AC voltage. How do you chop the mains voltage (probably after rectifying it)?
Every circuit type of smps has a unique input voltage V1(f,t), Z1(f,t) and unique output V2(f,t), Z2(f,t) in s parameters these can either all voltage or current or all impedances where s11 is input and s22 is output for a 2 port device. The forward transfer function is s12 and reverse is s21. Load regulation is due to the ratio of (...)
We are advised to use any input voltage sources.
I see a lot of problems with this design from dI/dt coupling, conductive losses on traces, no short circuit :sad: withstanding p rotection, no high voltage(3kV isolation from arcing. Start over using busbars with common mode paths on opposite sides of insuator yet high voltage insulation with 1kA surge capability.