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158 Threads found on Power Supply Coupling
Hi there, I am designing a circuit, and using a 3A Switcher for my power supply. I am using an ultrasonic sensor that says it can draw up to 2A when active. How should I protect this from bringing the rest of my rails down? Is Bulk capacitance/series resistance good enough, or should I filter out my other devices more than just a simple decoupl
Hi All, Please give me details of voltage regulator or LDO for generating 1.2V. Thanks, Gold_kiss If you like a plug-and-play solution see: only one resistor to generate any value from 0.76 to 3.6 v starting from 3v to 5V input
Dear All, Could you please, help me to understand this topic Adaptive power-supply Regulation for PLLs Thanks Rania
Hello, with friends work on precision laboratory power supply 0-50V 0-10A with 16bit digital control. In first step we design dc step down with Synchronous Buck Controller LM5116, in second step precision linear regulation see below on picture. Digital control is MCU with 24bit ADC and 16bit DAC , control voltage 0-10V Question 1. (...)
You don't measure the input power. It's actually V1*I(V1). As a hint: You can also determine the power factor from an I1 fourier transformation respectively THD measurement.
Hi! I'm working on designing a touch button using pico power AVR microcontroller. upon detecting a touch, the system should activate an AC appliance. For that i will use a triac. The whole circuit should consume no more than 1 mA at 2V. Now I'm searching for the best way to power this circuit from the AC mains without using a bulky (...)
why we use dual power supply in op amps ??? :roll:
You shouldn't need more than a few uF for the microcontroller. If it requires more, then something isn't working right. Are the heatsinks you added to the H bridge electrically isolated from the H bridge? You'll have to post a schematic showing how your MCU and its power supply is related to the H bridge. I agree, w
Hi Friends, I really facing big issue with the isolation issue in our circuitry. We isolated the microcontroller power supply from other noisy power supply completely. There is no direct connection between these grounds at all. But, I observed 400mV noise at the microcontroller pin even though it is not (...)
Hi All, I need to feed the board power supply via a 3-meter cable(dc power supply is generating on the mother board). I just wonder how can we calculate a suitable de-coupling capacitor value in this situation? We always use a big enough cap and low esr type but is there any proper way to calculate the (...)
From your power supply limits, BJTs are the way to go if the frequency response does not need to go very low. Otherwise, the coupling capacitors and bypass capacitors will run the cost up. You may be stuck with operational amplifiers.
Well i guess you mean how to use the op-amps which need dual power supply ,well for this case there is some ct. which makes dc-dc converstion so some ct take the 9v and converts it to +4V , -4V and GND ofcourse
just an easy idea: On your power supply side you need a resistor and a differential amp to measure the current through the supply lines. On the ?C side you connect a port pin to a transistor that will draw some current from the power lines. thats all for unidirectional communication. More complicated will be (...)
Hi everybody I have designed a flyback power supply by uc3844 and i have 5 isolated slave outputs, one of them is for 3844 Vcc and i want to use 4 others in my system. I have isolated the master output feedback (+12) by means of optocoupler and my load regulation in master output is so good (from no load to 3 amperes). I have a little ga
Yes, it just isolates high voltage and low voltage power system and pretects low voltage device.
The time constant of the RC is 5 us and your signal period is 2% of this so there will be little pulse distortion. The average signal on the right is the power supply voltage. The AC component of the input gets put across the capacitor so you will get on the transistor side the same shaped waveform but with the high Vcc+0.1 and the low Vcc-0.1.
C1 filters the power supply to the first stage. This prevents oscillations from power supply coupling. The noise of the input resistor is amplified by the transistor stages. The noise voltage is proportional to the square root of the resistance. The two parallel capacitors bypass over a wider (...)
Hi, Can you recommend me good power line filter? I need a filter to protect my device from noise entering from the mains. There is a uC with ADC on the board and sometimes when an inductive load is switched ON/OFF on the same phase all things just freeze. There are a voltage supervisor and a watch dog timer but in the most cases they
I think a more power dissipation has to be consumed if you want to get a low noise BandGap. And , get a high PSR to reduce the power supply coupling. In order to get low flicker noise, user large area MOS to get the reference. Add the guard ring as possible as you can to decrease the susbtrate noise (...)
Hi, I have a 3V power supply. I am using a op (IC 741) with 3v and ground... Is there an easy way to use it with 3v and -3v...? I cannot change the power supply. I get a signal from an electret microphone. I use a capacity to get rid of AC signal, but after using the opamp as preamplifier with (factor 22) I get a (...)
how do this configuration don't know how different connection method of gnda/gnd can improve the power isolation, any paper or reference ? thank you!
In DC applications (or AC with DC component ) while running of single power supply you need to create so called "virtual ground" (1/2Vcc), in AC applications this issue is solved by adding an output coupling capacitor .. If you don't want or don't like the idea of virtual ground or coupling caps then the only answer is dual (...)
Without looking at a specific op-amp, these are my suggestions/comments: Since power supply Rejection Ratio is the Gain from the power supply to the output rejected by the open loop gain of the amplifier: 1. Make sure you have a high open loop gain 2. power supply noise (...)
Can any body tell material about ac coupling of single ended input (32Khz) . A capacitor in series with self biased inverter(resistor connected to in and out of the inverter) works as a ac couple circuit. I want to know how power supply noise can effect the output. And how to set the bandpass limits? Is design requirement changes with (...)
Hi all. I wish I had found this forum a little sooner. I'm trying to design a RF power amplifier to work at 13.56Mhz. I'm trying to amplify the transmit power from a Texas Instrument TRF7960 reader IC. I want an output power of 8 Watts to power up an antenna that I have built. Reason for this much power (...)
What is the circuit that will be powered with plus and minus 4.5V? Post it and we will show you how to bias it so it works with only a +9V supply.
Hey I'm working on a wireless battery charger design. So far, i have inductive coupling to power up a PLL based battery charging circuit. each circuit works fine in isolation. but when together and when the whole circuit is off, the battery back powers the rest of the circuit rendering it ON even when its supposed to be off. I want to (...)
Hi Use a low ohm resistor (10 ohm or less) in series with the + line connect a short switch (best on power mosfet + driver ) after the resistor between the + and Gnd.(shorting the PSU when conducting) the resistor is power limiting and for avoid shorting the power supply Connect a current sense amplifier (INA138) (...)
Is it necessary to remove the copper from ground and power plane under the ferrite and common mode chock,
Well for one as you may know the noise of the total system in this case: F = F1 +F2-1/Gain1 From this equation you can see that the Noise Figure (F) is dominated by the first stage. This mean you have to make sure that the gain of the first stage is sufficient to support the second. Also you can also experience loss due to unmatched inputs a
It is a power amplifier based on SymAsym modules. power of transformer is 200VA and voltage of 2x28V. power supply consists of two rectifier bridges 8A and ten capacitors with a capacitance of 4700uF/50V Nippon Chemi
You may be concerned with line transients coupling into your DC, so current limiting with TVS OVP is recommended. For OR'ing DC power, I would think "high man win's " diode OR'ing would be sufficient with low voltage loss (from low current ) and no need to care which is active unless you add LED monitor from non-pattery power to indicate (...)
It is a stereo full tube (2x18W) guitar power amplifier, adapted to be mounted in a 19? rack. Housing height is 2U. The construction is more simple than similar devices from Marshall or Mesa. It is based on a typical
Under 1 (above) there is also inductive coupling. this is very popular at RF, where a tuned circuit has to be used, an additional few turns of wire around your main tuning inductor, and you have an impedance match and DC isolation. Most power supply units use inductive coupling with transformers to isolate the circuits from (...)
Hello, I had designed circuit using 555 in its monostable mode. the circuit works fine. but the problem now is when i power on the system, sometimes the output gets triggered with out giving input to the triggering pin. i have attached my circuit diagram with the post. This is a serious problem, because i use a 12v transformer with 7812 and w
Hi,my self Pradeep doing M-Tech in RF comm.I have taken power amplifier for my final sem project. It's specifications are Freq range 30-512Mhz, power supply is 7.5V and 1.2A. Input power -5dbm(0.316mW). output power is 5W. with this i also need to achieve IMD3,ACPR,NF etc. I am using AWR tool for my design. (...)
I would like to add here a special warning regarding tantalum capacitors: They may burn violently, and cause fire hazard, and also emit toxic fumes, if they are failing either due to over-voltage or reversal. That happens very easily, if the power supply has sufficient current capacity! Therefore: If you "misuse" aluminum electrolytic capacit
Hi All, am designing power line communication light control device using PL3170 please any one tell me how to interface this to AC(230V) supply, Thanks in Advance, Kingssk
Hello Everyone, Project I currently working is about a power supply for powering X-Ray tube. I would like to get more information about this topic and some help from you guys, if you are so kind. I apologize for my bad English. So, my goal is to build a power supply with max. output voltage 100 - 120 (...)
It would be substantially easier to try to help you if you would tell exactly which chips you use and which power supply voltages are present. The more details you give for your particular design (even a fragment of the schematics might help), the more easier it is to understand the issue! Ted
be carefull when combining several independant switched power supplys!! Especially when each one is running with it's own frequency you can easiely increase output noise. No matter how good the filtering on the ouput of a smps is, you will always be able to destinguish between a switched and a conventional power supply. When (...)
>I push the on switch, the pc turns on 1 or 2 sec and goes off. Any similar problem there ? any fixs ? Is a power supply shut off each time? A power supply switch is pushed and seen immediately. After a power supply is shut off, how is it ? I have a ASUS P3B-1394 (Slot-1 M/B) (...)
Hi, What net frequency are they using in your country ?? if its 60 Hz then the frequency change could be 120 Hz... What R are you using in your RC osc ??.. try to reduce the R if its larger than 50K.. it is possible that your power supply is not clean and that a small signal of 120 Hz is there... try to power your device by batt and (...)
You can use an emitter follower as an oscillator but, due to its inherent instability, in this configuration the right topology to be used is the one that is known as a negative resistance topology. In this topology the collector is grounded for RF and DC, being the VCC applied to the emitter. If you have a problem with negative power supply, yo
My data converter is AD9863. My ADC sample clock is souced from FPGA. The sample clock from FPGA isn't clean. The ADC sample clock frequecy is 15Mhz.I find that noises are introduced into my system. I have some problems about Clock. The sample clock can be sourced from FPGA?If not,how can I do? Thanks a lot. first pla
The concept of leakage inductance is used to model the flux coupled with wone of the winding but not with the other. So the energy stored into the leakage inductance is not delivered across the transformer. Usually Leakage inductance is bad but it can somehow useful in multiple output Switching power supply to improve cross regulation. Nation
Differential PA in IC technology are more tolerant to common mode noise through power supply and substrate coupling. The performance of a differential PA is limited in terms of high power consumption, almost double of the single stage counterpart and low dynamic range. The cot of implementing differential PA in IC technology (...)
Hi I am working on the power line communication project. I have implemented FSK modulation and demodulation using XR2206 and XR2211 respectively. I am getting 30khz and 15KHz, 5Vpp output for logic 1 and logic 0 respectively. I have also implemented the coupling circuit using ferrite core from the power supply and (...)
Those are good answers. Another possible meaning ... An analog circuit with good DC balance will maintain stable DC performance (avoiding drift or offset) despite changes in temperature, power supply voltage, operating mode, etc.
I think it's another idea for transformerless power supply. You can try it with resistive load before working with the Batt. And please let us know your experiment's result.