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Hi, for what type of load grounded or not, reactive or active? What range of curent, and fixed current or floath, and if the range is floath what acuracy in %. Do you look for high eficient schem or any one is suitable for you.
hi... i would need a constant current source circuit with clamped voltage 5v... any1 can provide me the info? thx
there are notes for MOS arrays :
jackyhu2008, The circuit that you've posted is a current sensor, not a current source. - Nick Here's an app note with a couple of topologies for OpAmp current sources . In general, if you google "precision OpAmp current source", you'll get a lot (...)
Attached is a constant current source circuit delivering 100mA of current to charge a nimh battery 0V in the circuit represents fully discharged cell My problem is when the cell voltage reach 2.8V the current delived becomes 80mA instead of 100mA. whereas upto 2.4V the (...)
What's your requirement? Independent on regulation of current value? How about trying to generate a current source with Vbg/R. R can be an external resistor for accurate.
Hi, I want to create a current source circuit to connect to an already existing I to V converter. What i want to do is to vary the input current from 0-400uA and note the corresponding output voltage.currently for 10uA i get 100mV approximately at the 10 is the gain.(ignore the resistor valuesin (...)
file:///C:/Documents%20and%20Settings/naren/Desktop/BE%20PROJECT/current%20source/A%20Constant%20current%20source%20for%20a%20Grounded%20Load%20using%20a%20Single%20Op-Amp.htm this is the URL for current source circuit...here they have given thar capacitors are connected (...)
I'm designing an ADC in 0.18um CMOS technology and I need an accurate and stable current source circuit for that. I have a couple of current sources designed by myself but all of them will fail in corner analysis. I want to make sure that my current sources will work in all (...)
Q2 will turn on when there is ~0.6 volts across its base-emmitter, turning off Q1. So current through the doiodes is: 0.6/ 10 = 60mA. So R1 = 0.6/ Required current.
Hi guys. I have a question on a schematic that I am looking at. It is used as a variable current source, however I am just a little confused on how exactly it is working. It is attached. From what I gather, the 2 bits control how much voltage is present on the gate of p-MOS2 via potential dividers. I am a little confused about what the 2 p-MOS
I agree about the PMOS suggestion. An important advantage of the output transistor connected as source follower is less current dependent gain. For the compensation, I'm pretty sure that C1 should be used rather than C2. The latter doesn't cancel the gate capacitance related pole and may have difficulties to achieve stable behavior at all. C1 shoul
Hi all I am having a question about the diagram 97231 In this circuit, the dependent voltage control current source is decoupled the left-most resistor from the source. The left-most resistor doesn't receive anything from the source. I was trying to anaylsis with nodal/mesh analysis, but I have (...)
Hi, I need a current source circuit using PWM technique. I need to vary the current from 0 to 1A by varying pulse width of 100HZ frequency signal. Please reply...
Friends, I need to make a Stable AC current source.... It should be able to vary the current using a Potentiometer from 1A to 5A of about 100VA rating....
Hello brothers! I have one problem: I am design a PWM circuit that control the current source in galvanometer(speed meter). The manufacturer of the galvanometer (speed meter) specify the following conditions: 60Hz, 0...25mA; speed show proportional of the pulse current throught of the coil. I design the (...)
one current source is propportional to absolute temperature, another is negative temperature coefficient. and there are only bipolar transistors in the circuit. in other words , there can not be mos transistor in the circuit. thanks
Hi all, i have a problem during bench test. i am using current source as a load to my LDO. if i set my current source to about -50mA and turn on my supply for the circuit my meter will read an almost -0.7V which i thinks is the voltage of my forwarded ESD diode. however, if my SUpply is (...)
Your post doesn't make much sense. If I understand correctly you are making a constant current source but I have no idea what you mean with the rest of your description about the supply of the remaining design that should not have any power supply etc. Alex
Hi Guys!! I'm developing a receiver circuit for an ultrasonic powered neurostimulator. Could someone please help me with extracting clock ( clock extraction circuit ) from a current source (in my thesis, it's a capacitive micromachined ultrasonic transducer-cmut). I need to feed the clock signal extracted from cmut to the (...)
If you short a current source you still get the current source current. So a perfect 1A current source will deliver 1A whatever the load - zero or 1M ohm. A real current source will not be quite as good. Keith
How do you specify the dependent current source(i=gm*exp(-jwt) in the spice model for generating the small signal equivalent circuit of FET?
I need a design hint for a adjustable current sink or current source. I want to control the current through a solenoid (hydraulic control). The current must be adjustable by a voltage (DAC). It should be a closed loop control. The current is in the range from 50mA to 1500mA. The supply (...)
Hello all, Does anybody out there has constant current source circuits which is suitable for electrochemical application (e.g. plating)? This circuit should be adjustable (current setting) and has maximum current rating at least 2 A. Thank you in advance :D
Hi there, I need to design a 10nA DC current source, stable DC output. Anybody can help? Thanks in advance. Yours,
Hi i want to desing 20mA constat current source/sink circuit. My supply is varying from 2.2 - 3.4 Volts. Can anyone help me to design the same? how can i maintain constant current throughout this supply range its urgent please help me thanks ~niks~
Hi this circuit look like strange .. output use "invert" stage .. I think it will have large THD when input is small input .. what not use class_AB stage ? and I only know some output stage use common_source + current load --> Razavi have a good book "design of Analog CMOS integrated circuit "
Half wave rectify a sine wave oscillator output and put the resulting to a voltage to current converter.
please specify your requirements; 50 nA is too low to control on chip since it is comparable to leakage currents or even cross talk to other signals on the chip will corrupt its value/accuracy. in this cases, the system or circuit topology/technique must be changed! BEST!
Voltge is like the pressure of water and current is like the flow of water. Voltage source means measure the pressure of water at that point and current source means measure the flow of water at that point rather than measure the pressure.
hi! i need a constant current source that can be adjusted with pwm. (about 1.5-2 A). is there such a circuit?
After finished a DAC design, I found that the bandgap output voltage can not bias DAC directly. So I need a current mirror circuit to bias the current source array in DAC (current steering architecture) . This circuit can change the bandgap output voltage to current. A paper (...)
Hello! If you need acurate current source you could use several Texas Instruments (w*w.ti.com) current references REF200AU. Regards!
Dear All, I've tried to simulate a current-controlled current source(CCCS) in Hspice. Refer to the diagram, and the syntax for CCCS is: Fcccs1 Iout gnd Vsen 0.5 Vsen A gnd 0 My question is : Vsen voltage souce should be 0v or 0.5v (1/2 of the 1v), why? Thanks in advance... regards, smart
Can PTAT? current source be implemented by CMOS only? Anybody has the circuit? Thanks
just remember it this way: an ideal current source is represented by a nortons model:a current source in parallel witha a resistance,so when this parallel resiatnce becomes infinite then the whole of the current sourced by the current source reaches the (...)
I don't think you need another external 1A constant current source to drive this circuit. As you can see from, for example, Fig.3 (data sheet) by selecting 0.125Ω current setting resistor the current in this circuit is set to 1A, so what you need is a voltage source (...)
I am Sorry, I made a mistake about length and width of PMOS . I modify it linke attach file In your layout ,I think the top figure is better than other one. the effect of VGS is more than VGD in current mirror circuit.
For CMOS VCO design, T.H Lee and Ali said to bias VCO to the point before Voltage limited to achieve the best phase noise. And also the symmetry of the wavefrom can reduce the flicker noise upconversion. But there is a problem is, for the VCO with tail current source, if bias the circuit to achieve the symmetry, normally the tail (...)
Dear all, If I have want to model my current source layout(permutation), how do I do? Which tool do I use? How do I do? Thanks.
In case of a constant current source at first the current will flow at contant rate, so the voltage increase will be linear, but if it is not ideal case where the supply voltage is infinite, finally, the current will decrease --> it asymptotically approaches zero for longer, and longer times. Similarly the charge (voltage) (...)
hi :?: please help me quikly :cry: i wanted a cirrcuit with current controll i
Can anyone post a circuit of a Basic current source using p-channel mirror for generating 0.35mA using 0.18um? Regards, Faraday.
Hello friends, I tried to search for schematic on this forum but I wasn't find any schematic i got over 7000 matches. Can someone post me some, good one, schematic for current source (or link to it), (I want to use precise (10 or more round) potentiometer to change current), with transistors or OP amp or you tell me. Thank you in (...)
I am trying to build a current source that could deliver about 800mA current. It is meant for a battery Charger. I simulated the circuit for 70mA. Then I started to look for commercially available current source ICs. Most ICs supplied not more than 10uA to 10mA. Is a current (...)
I am looking for a high effeciency voltage controlled constant current source for driving and dimming 3W White LED's. I saw the solution provided by IanP over here but I think effeciency is an issue in that circuit as resistor R1 will dissipate considerable amount of power which is not desirable when usin
I need to make a current detection circuit for a Diode. and please help me to find a IC or a good circuit to detect the current. a brief description is: The cathod of the diode is GNDed via a current source and the anode of the diode is connected with Vcc directly. the purpose of the (...)
hello i need a current source for LDO's opamp. Vin changes from 1.3 to 3.3 so i need something voltage independent. simple use of resistor to create a reference current is very inacurrate. what can i use with so high voltage change?
I have a circuit I am treating as a "black box" but it involves a switching regulator. I am trying to "inject current" into the feedback loop of the regulator in order to change the output voltage, but I find that when I do so, it throws both the circuit involving the regulator, and the current source I have (...)
Very useful circuit, whoose idea is to make equal Vds voltages of two pmos, which results in ideal current matching. Amplifier is just used to set DC voltage gate voltage of current current mirror gate. So I see this circuit like ideally matched current mirror. If you want to calculate (...)