Salas
I finished that schematic but Instead of 24 V I get 6.6 V dc at output
Is that normal
what Is formula to calculate Vout
A friend made the same and had all the voltage he told me. To calculate vout with a passive voltage reference you measure voltage drop across the 1k resistor at Mosfet gate to ground. That voltage/1000 is the current in A through the mirror. Then you know that most of your vout should be the drop across the Vref resistor or trimmer for mirror's current times trimmer's R as in Ohm's law. Then you add the LED voltage and the two Vbe drops (~0.65+0.65V) of the right hand mirror transistors.
Having some connection error or some oscillation maybe gives you weird result. You should use the trimmer connected as a rheostat for instance. Done such? Another very good solution since there is a high value filter capacitor is to use a Zener with cathode looking up north instead of a passive. A 20V 0.5W one. That would give you ~23.3V with a red led and if nearer 24V is a must, you can add a generic silicon diode in series with the LED in same cathode orientation as the Led. If little bit is needed still, change the LED to green.
Having some connection error or some oscillation maybe gives you weird result. You should use the trimmer connected as a rheostat for instance. Done such? Another very good solution since there is a high value filter capacitor is to use a Zener with cathode looking up north instead of a passive. A 20V 0.5W one. That would give you ~23.3V with a red led and if nearer 24V is a must, you can add a generic silicon diode in series with the LED in same cathode orientation as the Led. If little bit is needed still, change the LED to green.
No, that represents a very low VGS of the output Mosfet. I wonder what is the exact type you used, if it is oriented correctly, and/or there is enough current from the main CCS to open it correctly. Tell me what value is the CCS setting resistor you used, if there is one Vbe voltage drop across it, and what value is your test dummy load?
So 0.6/5=120mA available from the main CCS. An STP55NF06 I check right now is easily turned on to VGS ON of 3.216V with just 5mA on DCA pro checker. I would expect the L version to show at least a couple of volts. Something's surely going wrong. See if there is a bad apple STP by exchanging with another one first. If all circuit connections & orientations are right and the Mosfet is alright, then only oscillation can give such weird results. Is there a photo of the build available?
Check that the mirror is arranged correctly for connections and orientations of the 4403s. 3.7V over 1K means 3.7mA that must copy to the mirror's other side and drive the resistor you use predictably for voltage ref. If all looks right then its oscillation due to some layout factor. Do you have an oscilloscope?
I got to tell you that STP55NF0L was fault ( probably overheated with soldering) - It was Vgs 0.6 V not more
but with IRF740 I got almost same result at output
Is there a way to catch an error at 4403 output transistors as they look correct connected but I am not sure that they are not fault - maybe some test point to measure voltage
but with IRF740 I got almost same result at output
Is there a way to catch an error at 4403 output transistors as they look correct connected but I am not sure that they are not fault - maybe some test point to measure voltage
In general, in what conditions and for what components is overheating a problem?
This is new info that you used just 3k9 after the Mosfet fix. ~3.7mA X 3.9K= ~14V so your reg started behaving right. Use proper value as I explained how to calculate everything that adds up for Vout. If there are thermal wanderings at 24V with passive use the Zener I described which and how.
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