41 Threads found on edaboard.com: Power Supply Coupling
1) what are your voltages? supply, input, output.
2) You tell us p-p voltage, but what's common-mode voltage? You might be pinned up against your power supply rail.
3) HOW are you adjusting your gain? In the diff amp? In the second stage?
4) what is your frequency? AC coupling is not going to work very well below some frequency.
Analog Circuit Design :: 02-08-2017 17:10 :: barry :: Replies: 9 :: Views: 410
I have a 1.25 kW LDMOS amplifier. It works fine at low powers of about 100 W. But beyond that I see an increase in the display on the power supply for the Gate to Source Voltage and Drain current increases too. The CRO also shows a fluctuating pulse. The output power on the power meter fluctuates a lot too. (...)
RF, Microwave, Antennas and Optics :: 11-25-2016 03:37 :: Twisha :: Replies: 3 :: Views: 336
How do you do load pull on a differential pair to know the optimum load impedance for the transistor? Do you just use one single transistor instead?
A real design (either IC or discrete) will have some coupling between both output transistors, also a non-zero power supply impedance. So the impedance of the differential stage is d
RF, Microwave, Antennas and Optics :: 10-07-2016 05:05 :: FvM :: Replies: 1 :: Views: 333
The input voltage comes from a 3V linear regulator
The input_voltage or the supply_voltage for the OPAMP?
but I need it to be as flat and stable as possible: noise and drift are an issue. The output will be used as a ground reference for an amplifier.
Please try to input "as flat as possible" to your calculator..
Analog Circuit Design :: 07-21-2016 10:44 :: KlausST :: Replies: 18 :: Views: 406
There is confusion about if the capacitor is for decoupling (filtering the power supply voltage) or coupling a signal from the output of one stage to the input of the next stage.
The first post says to cancel (block) DC but pass the AC signal and correctly calls it a highpass filter so it is a coupling (...)
Analog Circuit Design :: 04-22-2016 01:17 :: Audioguru :: Replies: 3 :: Views: 398
It is easy to power the LM358 because it works with a power supply that is from 3V to 32V.
You do not need a "virtual ground", instead you bias the (+) input to half the supply voltage with two or three resistors and maybe a filter capacitor. Then the input, output and feedback to ground need coupling (...)
Analog Circuit Design :: 10-05-2015 03:30 :: Audioguru :: Replies: 8 :: Views: 1002
Bypass or decoupling capacitors are usually placed across low impedance power supply sources (~0.1 ohm). To acheive enough attenuation of noise greater the capacitor is. Blocking or coupling capacitor must have enough low reactance regarding to source and load impedances (50 ohm) not to introduce attenuation losses.
RF, Microwave, Antennas and Optics :: 06-19-2015 14:33 :: Borber :: Replies: 7 :: Views: 816
hi I need to make a 13.56Mhz power supply with about 1000 V - 2000 V output voltage....
can you give more on what is "13.56Mhz power supply"?
and 1000v-2000v ? where it is reqd ?
RF, Microwave, Antennas and Optics :: 04-28-2015 07:17 :: srizbf :: Replies: 6 :: Views: 432
Either voltage or current mode bias distribution has its
plusses and minuses. With voltage mode you worry about
ground offsets and cross-chip VT gradients. With current
mode, especially very low currents (hence high net
impedance) you worry about signal coupling from digital
aggressors and HF power supply noise. Which of these
is worse, (...)
Analog Integrated Circuit (IC) Design, Layout and Fabrication :: 10-24-2014 16:45 :: dick_freebird :: Replies: 10 :: Views: 1395
I get hold on a 30 V 3A dual bench power supply Selectronic SL-1731SB, which seems to be the same
as the Velleman PS23023, and may some other ones.
Both canals are OK, but when I coupled them in series, the coupling is totally wrong
Tracking not activated : A : 5.4 V B: 10.3 V
Tracking activated : A :25 V (...)
Service Manuals, Requests, Repair Tips :: 10-12-2014 19:50 :: JacquesBBB :: Replies: 1 :: Views: 1123
1st check output power, and supply current. The collector should be twice the supply voltage p-p when On. Can you increase power with battery voltage?
. Then fix coupling cap to antenna with a much smaller value to tune impedance to antenna and resonate at 450MHz. L2 is required for this.
what is the load (...)
RF, Microwave, Antennas and Optics :: 08-20-2014 07:09 :: SunnySkyguy :: Replies: 3 :: Views: 989
Random noise in resistors and transistors
Undesired cross-coupling noise
power supply noise
EMI, Co-channel, Adjacent channel, cosmic noise, power Line transients
SNR= Signal power/Noise power
Analog Circuit Design :: 06-07-2014 01:49 :: SunnySkyguy :: Replies: 4 :: Views: 837
Can you shield one of them ??Or both ??? The single practical solution that you may apply..
Picks may also come from power supply if they share the same supply lines. Ferrite beads will cutt-off the interference.
Grounds are also important if they share some ground lines ..
RF, Microwave, Antennas and Optics :: 01-19-2014 13:04 :: BigBoss :: Replies: 2 :: Views: 460
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 (...)
Power Electronics :: 07-30-2013 12:35 :: S0syk :: Replies: 6 :: Views: 1584
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,
Elementary Electronic Questions :: 06-26-2013 11:54 :: kingssk :: Replies: 2 :: Views: 620
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
Elementary Electronic Questions :: 05-31-2013 07:39 :: ted :: Replies: 8 :: Views: 1731
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 (...)
Analog Circuit Design :: 05-16-2013 07:50 :: kudjung :: Replies: 2 :: Views: 566
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 (...)
Elementary Electronic Questions :: 12-17-2012 16:41 :: chuckey :: Replies: 2 :: Views: 881
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 (...)
Analog Circuit Design :: 08-07-2012 16:00 :: SunnySkyguy :: Replies: 25 :: Views: 3621
May be you could avoid draw power plane under that components.
But, I can´t see any problem to route ground there.
PCB Routing Schematic Layout software and Simulation :: 03-18-2011 11:09 :: andre_teprom :: Replies: 4 :: Views: 1886
The transition npn-pnp-npn is because of the dc level of the three operating points.
But the AC coupling would allow three npn as well. An advantage of this circuit is in better rejection of power supply interferences (higher power supply rejection ratio PSRR).
It's a circuit, that one would demonstrate (...)
Analog Circuit Design :: 02-05-2011 10:59 :: FvM :: Replies: 5 :: Views: 647
The amplifier has 400 overall gain with about 150 MHz bandwidth. It's very easy to get oscillations by unwanted coupling between input and
output or through power supply. Apparently, you didn't use a suitable "RF" circuit layout. A continuous ground plane and additional supply
decoupling by ferrite beads (...)
Analog Circuit Design :: 05-28-2010 05:49 :: FvM :: Replies: 6 :: Views: 1835
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 (...)
Power Electronics :: 11-09-2009 16:48 :: temporysing :: Replies: 0 :: Views: 964
I Simulate one flyback switching power supply with this specification in Orcad 16 cadence.
Vin=24 v (DC) Vout=1300 v (DC) Iout=40 mA
L1=43uH L2=150mH coupling=0.99
I have a problem in snubber circuit. I want to reduce spike voltage to minimum range and reduce ring voltage frequency. is it possible?
please help me to improve it.
Analog Circuit Design :: 10-18-2009 18:43 :: tictac :: Replies: 4 :: Views: 2864
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.
Hobby Circuits and Small Projects Problems :: 04-23-2009 01:27 :: Audioguru :: Replies: 8 :: Views: 13945
Some devices draw large amounts of transient current while they are switching. These currents can have very short rise times. Because of the inductance in the PWB tracks, this causes a momentary drop in voltage at the device power terminals. A capacitor placed close to the device provides a low inductance voltage supply, thus preventing t
Elementary Electronic Questions :: 02-02-2009 16:09 :: Kral :: Replies: 3 :: Views: 2357
Opto isolator will help if the noise you are seeing is due to ground coupling. You can use 6N137 type opto and you should use it at the TTL level before RS485, at the output of the Micro. You should then use an isolated power supply to power the 485 ICs and isolated section of the opto. You can derive this (...)
Microcontrollers :: 02-22-2008 18:50 :: laktronics :: Replies: 5 :: Views: 2775
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 (...)
Analog Circuit Design :: 01-09-2008 09:12 :: shashidhar pati :: Replies: 1 :: Views: 735
ASIC Design Methodologies and Tools (Digital) :: 11-01-2007 13:06 :: littlefield :: Replies: 7 :: Views: 1060
I have some query related to custom Layout:
1. Why we connect all dummy pattern to Low potential ( VSS or AVSS)
power supply, Why not to highest potential ( VDD or AVDD) power
2. If a sensitive net ( any High frequency net) passing over dummy
pattern , Will it create any problem?
Should we avoid
Analog Integrated Circuit (IC) Design, Layout and Fabrication :: 10-12-2007 13:42 :: protonixs :: Replies: 8 :: Views: 4277
It just a de-coupling circuit for your power supply. To provid more clearly power for your analog IC.
Analog Circuit Design :: 06-19-2006 15:52 :: Wenye :: Replies: 2 :: Views: 869
the main isssue in mixed signal soc is SUBSTRATE coupling and power supply NOISE. refer some ieee papers to get to know about it
ASIC Design Methodologies and Tools (Digital) :: 06-16-2006 08:26 :: nav_vlsi :: Replies: 1 :: Views: 1000
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 (...)
Analog Circuit Design :: 12-25-2005 05:06 :: jiangwp :: Replies: 3 :: Views: 1153
Unstable power supply voltage causes unstable signal parameters or erratic signal proccessing, unstable operation. Regulator low output resistance minimize parasitic feedback coupling through power supply line.
Most digital IC's require supply voltage with tight tollerances.
Analog Circuit Design :: 11-30-2005 11:54 :: Borber :: Replies: 17 :: Views: 1301
For analog design:
If the process is cmos , i think the soure follows can be used.
If the bipolar process, the emitter follows can be used.
For digital design:
The 2.5v power supply has to be need, and a cross-coupling feedback is to supply what you want.
Analog Circuit Design :: 09-04-2005 07:06 :: jiangwp :: Replies: 8 :: Views: 1418
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 (...)
Hobby Circuits and Small Projects Problems :: 07-22-2005 23:06 :: flatulent :: Replies: 10 :: Views: 3858
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.
Analog Circuit Design :: 07-15-2005 14:26 :: flatulent :: Replies: 10 :: Views: 1078
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 (...)
Analog Circuit Design :: 04-03-2005 17:19 :: ss :: Replies: 0 :: Views: 1420
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 (...)
Analog Integrated Circuit (IC) Design, Layout and Fabrication :: 11-20-2004 03:06 :: hrkhari :: Replies: 2 :: Views: 2897
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
Elementary Electronic Questions :: 08-03-2004 14:39 :: ahmed osama :: Replies: 3 :: Views: 1999
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.
Analog Circuit Design :: 06-01-2004 23:07 :: flatulent :: Replies: 9 :: Views: 1320