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denci
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Posts posted by denci
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Sorry I took a picture quickly with phone and bad light i just want to show example where to put ZXCT because i did not get a reliable resault before at output pin of ZXCT.
I didn't draw a power supply but i have it off course, it is 24V and i took LM324 which have common-mode voltage range.
I took into account of base current of battery discharging also, this is the reason why i want to measure current via current monitor.
so i should put the ZXCT as mentioned, this is what made me confused. -
The IC is called and is shown as a high side current sensor but you connected it as a low side current sensor so of course it WILL NOT WORK!
Hi...a long time ago i asked a question about ZXCT placement in circuit and i started a project again and i will continue where i stayed, so i have one question.
In circuit below, which represent microcontroler (PWM) regulated discharge current/power with OP folower as we can see, where where shpuld i place the ZXCT1107 and shunt for measuring in circuit to ensure me relevant information about current??
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I finished with working on power supply and made a test yesterday but just one think is not working properly, i can adjust the current only up to 3A then current blocking turning on.
I use elements for 5A project (Redwire) as i mentoined couple of times above but i have not idea where is the problem, i hope that i didn't overlook some element value, i will make a review of all elements in circuit once again. -
The MJ15003 is a good power transistor. The thermal Resistance, junction to case is about the lowest you can get but getting that to transfer to the heat sink is more difficult. The power derating of 1.43 W/C is high if you are running hot but when you start at 250W you've got plently of headroom. Have you checked out the MJ11016 it is a darlington transistor and if you don't mind a 1v drop (or less) in the total output, it has a gain of 1000 and will reduce the load on the BD139. The thermal Resistance, junction to case is close to the MJ15003. I did a test with only one MJ11016 driving a 5A-12v load on a large heat sink (outside a case) with no fan for about 5 minutes without failure. The BD139 only had a small heat sink and did not get that hot. I would feel very confortable with 3 transistors no matter what type (MJ15003, 2N5886 or MJ11016), running 5-7 amps.
A have been working on this a log time ago and i have just one question for you, which element in circuit is total allowed output current adepend on??
And just one thing, is project according to your parts list work properly at all or you did some changes on project, i am talking about 5A modified project, last table i have is below.
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Any idea?
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OK, I fixed the problem and i put the ZXCT1109 as shown in datasheet but i still have one problem.
If i want to get 0-5V output voltage and 0-10A sensing current i must put the Rsense of volue 10mE and Rgain 12,5kE, i get equations in datasheet.
But now i testnig the proper function of this measurments and i get 140mV in output with sense voltage 8,5mV and 410mV with sense voltage 16,4mV.
This is not what i want and not as calculated, it must be something wrong because i should get 0,5V in output with 1A (10mV sense voltage) current and so on, therefore 2A/V resolution??
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denci, none
You mean "none" about changing elements in circuit or you said that i can't use the three MJ series and decrease temperature on heatsink and transistor case due the better thermal resistance (0.7)? -
Therefore i can use three transistor any of MJ series on my heatsink but which element in circuit must be changed before running the PSU??
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Yes, i made PSU with new part list for 5A (redwire) and use new circuit with three 2N3055 transistor, but i thinking about replacing this transistor with better one, maybe with MJ15003, which have better thermal resistance (0.7°C/W) therefore dont,t need cooler to decreasing the temperature on heatsink and transistor case.
In this case, which element must be change in circuit if I want to use this alternative?
That's what I am thinking about... -
I finally made this PS and except for a few necessary values of element changes work fine.
I think that I should change the transistor 2N3055 with other alternative transistor with same spacification because is very hot by increasing the current to 5A. I can also add the 4. 2N3055, i bought heatsink with 4 TO-3 hole but i don't see the point in this.
Maybe have anyone some advice for this?
Which element in circuit must be changed due the transistor replacement? -
Any idea??
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I made a battery analyzer, which can analyze the battery and discharge it. I can set up the discharge current with pwm controled voltage regulated through resistor. Voltage on resistor limitc the current, which flow from battery. I did the mistake and i put ZXCT at the end of circuit, because i was not careful what is show in datasheet. This analyzer would also be possibility of charge the baterry and all circuit swithing between charge and discharge through two relay and therefore i put the current monitor at the and of circuit but i made a mistake as shown.
How can I avoid this problem? -
It is true but i have one resitor 0,47E before ZXCT current monitor, which is regulated by OPAMP pwm controled and limiting current is about 10Amps.
Therefore can I use onther 10mE resistor as load and sensing the current on this resistor, so i don't need to change my circuit, just put in the line??
I hope that it is understandable! -
I don't know if anybody makes a Low Side current sensor. It would be easy to make one.
What will happen, if i put another 10mE resistor as load, as i wrote above??
Will this work or not, i think that it should be work?? -
can anyone hlep me because im not really shure that i will solve this problem on that way
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What will happen, if i put another 10mE resistor as load, and than sensing the current.
It will work or not?
This may be the best solution for me, because otherwise i must change the way of current sensing -
Tnx,
so can I replace the existing chip (current monitor) with other, which have a low side current sensing?
Is there any ZXCT series alternative?? -
I tried to sense current with this methode but i can't read any voltage on output pin, which connect to the ADC pin of microconroller...
I don't know if problem has occured in circuit or anything else? -
Hi guys!
I want to sensing the current in my circuit (SLA battery tester) with current monitor IC ZXCT1109 but i have one question/issue?
Can i sense the current with Rload before the ZXCT or i need to use Rload as shown in datasheet?
Below is picture to best undertending:
In my case:
attach
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I have onother question, i don't know exactly where is the negative power supply in the schematic of stabilized power supply?
Therefore which connection in circuit should i use to negative set voltage (oV to -30V)?
Can anyone help me about this?? -
yes, that is what i meaned, but how to connect the adjustable pin of fine pot, together with adjustable pin of 10k pot??
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I have onother question, i don't know exactly where is the negative power supply in the schematic of stabilized power supply?
Therefore which connection in circuit should i use to negative set voltage (oV to -30V)? -
I think a large knob should be used for adjusting the voltage so you can see where it is and adjust it fine or coarse.
If you add a fine adjustment pot in series with the coarse adjusting pot then one pot will frequently be at its end.
So i must insert 1k pot in series with existing trim pot and adjustale pin combine together?? -
So i have build the power supply and i replaced sense resitor to 0.27E and i used three paralleled 2n3055 transistor with 0.33E emitor resistor.
I was thinking about max. current, how can i test this most easily??
Other component are unchanged against VER2 of circuit and REV3 of component!
Current monitor/sensor
in Electronic Projects Design/Ideas
Posted
Should i place shottky diode between transistor collector and load resistor for protection?
Voltage from OP folower feedback can occur also on transistor collector or no?