Programmable from 1µA to 10mA. □ ±3% initial accuracy. Description. The LM/LM/LM are 3-terminal adjustable current sources characterized by . LMM Texas Instruments Current & Power Monitors & Regulators NRND, alternate is LMM/NOPB datasheet, inventory, & pricing. LMM/NOPB Texas Instruments Current & Power Monitors & Regulators 3- TERM ADJ CURRENT SOURCE datasheet, inventory, & pricing.
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In the schematic, I1 represents the LM The circuit in this case is a Ground Continuity Monitor. Tyler Think of it rather as a current limiter. If anyone else has an idea of how to light an LED when daatasheet LM is actually limiting the current through it, that would work too.
LMM Datasheet(PDF) – National Semiconductor (TI)
Can R3 be replaced with an opto-isolator diode and series resistor? Sign up using Facebook. A small current datashheet an AC supply is intentionally “leaked” to ground. The divider produces about 0.
Please edit your question and delete the comment. Post as a guest Name. If the voltage is more than 2. Sign up or log in Sign up using Google. The trip point is intended to be no higher than ohms per volt – 10k. It belongs in the question. If the load impedance is high, then the current will be much lower than the limit.
In the old circuit, the output drives an optoisolator’s LED, but that circuit isn’t accurate or sensitive enough. If the load lm334 is low, then the current will hit the limit.
You need a different design, and I question the need for a current source. This isn’t superbly accurate, but might work well enough.
The typical performance is shown in the datasheet in this graph:. Sign up using Email and Password. When it’s passing less than 1 mA of current, I would adtasheet it to be acting like a very low-value resistor, meaning that the voltage drop across it should be low.
The simplest way to detect that would be by biasing a PNP transistor with a scaled-down version of l3m34m drop out voltage. Spehro Pefhany k 4 I need to use an opto between this lm334k and the logic systems for safety. When the 1 mA of current is reached, lm343m should begin to increase its resistance, thus increasing the voltage drop across it.
It’s not possible to give a good answer without much more information such as a complete schematic and accuracy requirements.
So for low currents, it might be delivering more-or-less constant current at 0. The current limiter is intended to limit the amount of ground leakage.
You can increase the resistance of the divider if you can use a larger load resistor R3 or a higher-gain transistor. The detection threshold would be something like 1V. I don’t see a way in circuitlab to represent an actual LM, so the simulation likely won’t operate correctly. All of that is true. Furthermore, I think datsaheet rather crazy that you allow such high ground impedance 10k.
My goal is to make an alarm of sorts when that impedance exceeds a threshold, and the way I want to do that is to detect when the is in current limiting mode.
The actual earth is on the far side of R1. A couple of resistors and a comparator with built-in reference would do the job in a much simpler fashion.
Note as well that the actual circuit ground is on the top side of R1 – Vout is the ground potential for the purpose of this circuit. Nov lm33m4 ’15 at R2 completely determines the behavior of the system, when looked at from outside, and sets the leakage current.
Othewise, the load is getting the maximum voltage that the source can provide, and is not running at full current. Kuba Ober 1, 10 One option would be a TL or LMV, but that’s just one of an almost infinite number of dtasheet. Usually when a current supplied less than the current required, there is a voltage drop. Any real km334m source will have a voltage limit beyond which it will not deliver a constant current.
LM from Texas Instruments