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81 Threads found on Error Amplifier Design
ENOB will always drop as frequency rises. You will have issues with the front end S/H amplifier tracking a faster-slewing signal. You could quantify the error at the hold node / A-D comparator front end.
Offset voltage and gain error terms need to support LSB accuracy. Bandwidth / settling time need to be well better than sampling rate, and settling time is to a very low residue error. You would have to design the amplifier for the worst case (max bits, max bit rate) or cases (if your scheme varies them independently or (...)
The same diodes + voltage divider level shift circuit can be found in many controller ICs with internal error amplifier. May be they just copied a design template. I don't see the purpose of asking "what's the purpose of". Just take it as is. The specified characteristic is achieved with this circuit in place.
Hi, I thought a regulator error amplifier needed a Vref on Vin+ and the feedback on Vin-, maybe I'm wrong for your design. What's a bandgap core? Home-made or manufactured? I ask as it's nice to learn things, and discrete voltage references are something I like but know will never be any good, and you're an IC designer. (...)
Hello everyone, I have to design a fully differential amplifier design. I have been given the following specs, How to calculate the gain and bandwidth of the amplifier: The given specs are: 1)Close Loop Gain 2)Max Input Step 3)Max Gain error 4)Max Settling error 5)Max Settling (...)
Since you know the amplitude error of the instrument why don't you add an "amplitude offset" to your SA ? Using an extra amplifier will increase the DANL of the SA.
I'm thinking at 2GSPS this is a RF application and you don't care about DC accuracy. If the sampling error is -constant- across the input range then maybe it gets processed out, no foul. Also at 2GSPS I'd think this is a 50-ohm system and you'd rather not have an amplifier to design, maybe this is just a dumb switch and the Cin of the (...)
Dear all, I am trying to design an avr for regulating the output of 230volt ac generator. avr input voltage-230 volt ac avr out put voltage -8 to 15 v feed back to generator excitation coil Please help me solve the error amplifier problem of sg3525 .I?m using sg 3525 with ir2010 Sync buck converter (...)
do you want to implement the error amplifier in software or in hardware.? If in software, then that is historically a hard job, unless arduino has some template software that you can shove values into. I send you example of voltage mode control, its not buck but you get to the point, its in ltspice. ltspice is free download. just change file
Dear All i have design a transconductance amplifier. done with layout of it.. cleared DRC and LVS and PEX. in PEX i m getting some warning. i m not able to understand those warning but because of these warning i m able to generate config view. i m attaching the error file
What is the ICMR or you Op-amp? What is the Output Voltage that you are targeting? Do the two match? You should have designed the entire LDO together and not in parts (error amplifier and then Power Transistor)
Both the inputs to your error amplifier are actually the outputs of your system. VLED and the Current. If VLED is 0V, then the Current and hence the INA210 output is also 0V. Therefore, both the inputs of the error amplifier are 0V, hence its output is 0V. This would mean that the PWM would never generate and the (...)
Probably uses a transconductance error amplifier rather than a voltage amplifier. This is common in many control ICs.
Hi guys, I am trying to do a PSS + PAC analysis using a VCVS. The schematic is this I am using these I don't know if I a
Hi, In one of the existing design I was working (pfc boost with UCC2818D controller) , I noticed that soft start is implemented by pulling the voltage error amplifier down through a diode (which will make multiplier output to zero) as shown in blue lines. This is done during startup and also some transient events when the boost duty cycle (...)
Hello everyone, I am new to low drop-out voltage(LDO) regulator design I have ever read a famous paper which tell me why PSRR get best reslut at low frequecny , 20db/dec degrading as frequency beyond error amplifier(EA) bandwidth, reach at worst case when frequency at the gain bandwidth product (GBW)of EA, 20db/dec increasing as (...)
Hi subbu2, This spec is little bit interesting. Look at the Vin variation 1.8 +/-10% means that the minimum voltage will be 1.62V. That means thee Power FET will have to provide 50mA current maintaining 1.5V at the output with only 120mV of VSD. Which again means that your Power FET will operate in linear region most of the time (specially when lo
I am working on the layout of instrumentation amplifier, my design is hierarchical i.e. there is three op amps in it. The layout of op amp is drc and lvs clean but when i instantiate the layout of op amp in the layout of instrumentation amplifier i got the lvs error. LVS error INCORRECT NETS (...)
Can I use the Vref (instead of dividing it) as one of the references for the error amplifier and then divide the 12V to 5V as the other reference for the error amplifier. Yes. Second: The power switch seems to be a pair of NPN=PNP transistors. Can anyone recommend alternate parts for these? The NTE153 and NTE331 are not av
Hello, I am designing a Power amplifier, The transistor selected is a freescale transistor (MRF6V2300N), luckily I have found its ADS design model, i have included it according to a tutorial, but while simulating it is giving following error.... Kindly guide how to correct this error?? any help is (...)
Hi, I am designing PWM based integrated DC-DC converter operating at 300MHz clock frequency. I need to do the stability analysis of whole circuit inorder to check whether the whole feeback system is stable or not. What kind of simulations i should do for that in cadence spectre RF?. What kind of error amplifier will be suitable for this (...)
Hi, I designed a class D switching converter with PWM feedback. Circuit diagram is attached. Now i am having problem in understanding the stability of overall PWM feedback. What should be the properties of error amplifier in this configuration. Moreover, though i have implemented PWM feedback using an opamp in summing configuration, i (...)
A reasonable controller design operates the TL494 with PI error amplifier and thus doesn't depend on opto coupler linearity for the static performance. That's how the industry standard TL431 opto isolated feedback works. Opto coupler transfer gain and gain non-linearity still matters for stable loop closure, but as said, this isn't a problem (...)
Reference voltage is for correcting error in your desired output by sensing the output voltage.
Greetings everyone, I'm trying to simulate a power amplifier and find the load-pull contours. I've done the state setup and the design set up as the spectreRF manual says. The thing is, spectre can't seem to understand the portAdapter symbol. When trying to simulate the design, I get an error as shown in the picture (...)
Before discussing the design of error amplifiers for PWM circuits, you should possibly understand the role of and necessary properties of error amplifiers in time continuous control loops. See e.g. Analysis of PWM systems is more complicated and mostly done in a simplified way by replacing the PWM pa
How we could the reason if you didn't show the circuit ??? post it so the people can identify the error I am to design a current source using transistors or opamps to get a constant current source of 10uA to connect it to a BJT differntial amplifier.the problem is current mirrors cannot work .
Can the output of a LDO be equal to the reference voltage ? or should it be always greater than the Vref. In a LDO structure consisting of error amplifier, pass device and resistive feedback. Can the output be equal to the Vref voltage ?
Hi, all How could I design a pretty low offset error amplifier (offset lower than 500uV)? Does it possible to using an autozero structure? Thanks
Hello. My design has a few comparators and a few opamps on board. Due to reasons like reduction of cost and board space, I am trying to use a comparator as an opamp in the error amplifier circuit. I believe STMicroelectronics has some related option, but when I search in the it is mostly about using an opamp as a comparator. Could any of
Beside OA offset errors, also need to consider on the input you apply a root mean square (abbreviated rms) sinusoidal signal and on the output you measure a peak value. U rms = U peak/1.41 20mV rms = 28.28mV peak
Hii, Generally compensation cap in error amplifier design of flyback smps is used for stability of power supply. I want to know how excatly the value of cap is determined, should we use a low value cap or a high value cap in the design. Regards Saurabh
Just use comparator to compare the two input signals for LDO error amplifier (output feedback voltage and reference voltage). If VfbVref+offset) can be used for overshoot suppression.
First, your schematic shows positive feedback: both your error amplifier and Pass Transistor are inverting. Exchange the inputs of the error amplifier! Can I design the Vx slightly less than vdd/2 to reduce the size of power mos? After having done the a.m. exchange, this is a regulation system. Vx (...)
Besides error amplifier, you need to design current bias, bandgap, OTP, current limiter.
Hi, I am doing amplifier design in Cadence vituoso and am using gpdk180 library my schematic and layout are complete, DRC and LVS successful, but when i try to extraxt(Run RCX) i get the error "No cellview for pcapacitor found" There are no paracitic components in gpdk180, how can i extract? Please Help.
What's the design spec for Buck converter? error amplifier design depends on the Buck system.
Hi How can i choose ICMR range of error should be depend upon this equation vin(min)>= Vref+Vsd+Vds correct or not(i used N type 2 stage opamp at 1.8 V supply)?? suppose in my design Vin(min) is 1.5V so my ICMRmax could be less then 1.5V but how can i choose ICMRmin ?? For error amp slew rate depend upon pass transistor driving v
Hi How can i choose ICMR range of error should be depend upon this equation vin(min)>= Vref+Vsd+Vds correct or not(i used N type 2 stage opamp at 1.8 V supply)?? suppose in my design Vin(min) is 1.5V so my ICMRmax could be less then 1.5V but how can i choose ICMRmin ?? For error amp slew rate depend upon pass transistor driving
Dear Forumites, Has anybody implemented error amplifier for compensation of regulator using Verilog-A. If so can anyone post the verilog-A code which can be used for type-2 compensation. I have tried creating one using model writer, but to the failure. So looking forward for some help. Ni1009
The reason I wanted to start afresh was that I was missing out on a lot of basic ideas to design a PWM controller. Aim: Class D amplifier design Disturbing thoughts : 1. How to know the optimum frequency of operation for the PWM. 2. How to finalize the specs for the amplifier, Comparator and error (...)
You can supply the error amplifier from the LDO output. The PSRR will be much higher in that case. But this circuit would require startup (which can be avoided as well).
hi guys, I am operating OP-AMP as a non-inverting amplifier. My problem is op-amp is not operating linearly. Always output = gain * input + offset. The problem is offset is not constant. It is varying with different values of input. I am attaching my schematic and data sheet TLE2142 of my design. Please let me know any error in the (...)
I think the schematic you are referring is: One error amplifier => PMOS. And the feedback path is connected back to non-inverting input of error amplifier. But you couldnt look at it and conclude it is positive feedback. If you look at whole system (error Amp + PMOS), it is equivalent to Negative (...)
In pwm to change duty cycle change I/P to error amplifier. If you can send schematic I can tell you better.
gain of error amplifier is >60 db is sufficient gain of buffer means its unity gain and total loop gain is sum of error amplifier gain+power mos gain(gmp*rop)+feedback path gain phase margin should be grater than 60 in order avoid ringing in output voltage waveform during transient conditions.
Hello, yxo I think the length of the second stage depends on what you want. If you use the first stage as an error amplifier to drive a pmos like you design a LDO, it is better to use smaller size. For conventional two stage amplifer design, I think it is better to keep the length of M16,M6,M7 the same to reduce offset, (...)
hi freinds; we have spoken later in (Problem with LDO design) about the positive and the negative feedback for the error amplifier and hopefully as LvW said, the PM is not always calculated by taking the origin in -180° and LVW has well explained it. so at this point, a question could be put: what is the difference between having a (...)
I would suggest passive filter in front of linear regulator. Higher freq are easier to address with passive, while lower end you could further suppress by linear regulator. If you make design that powers your error amplifier with output voltage, you could get better performance. In linear design floating psu for (...)
There are probably several ways. Maybe a PLL where you sample and compare the input and output signal and use the error signal to drive a phase shifter. You didn't mention if this was CW or a modulated signal.