0-30V Stabilized Power Supply

[denci]

http://www.changpuak.ch/electronics/calc_23.php

With this online claculator i have got the same results

[madafakamw]

Hi everyone,
I've made an online order for TLE2141 and i forgot to ask what package is build in. So i'm stuck with these.

Will my psu work?

[audioguru]

I've made an online order for TLE2141 and i forgot to ask what package is build in. So i'm stuck with these.
Will my psu work?

When the output current is 3A check that opamp U2 is not too hot.

[madafakamw]

Thank you for your quick reply. I will keep in touch.

[denci]

What is wrong with my heatsink calculation in 5 post ago??

[LEECH666]

I usually use this way to calculate the heatsink, it is wrong that way:
(130°C-30°C)/4.5W - (10C/W+0.3C/W) = 11,9°C/W

What is wrong with my heatsink calculation in 5 post ago??

Nothing wrong really.

Audioguru either made a small typo and actually wanted to type

(130°C - 76.4°C)/4.5W = 11.91K/W

or he substracted another 30°C of safety margin from the maximum junction temperature value of 130°C.

(130°C - 30°C - 76.4°C)/4.5W = 5.24K/W

Florian

[denci]

Tnx a lot!

[LEECH666]

In any case a smaller Kelvin per Watt value is always safer.
A heat sink with 5.24 K/W is most likely more expensive than one with 11.9 K/W.

Florian

[denci]

Where should i place the 1kohm pot3 for fine voltage regulation?

[xristost]

I finalized my second power supply unit. Now I may combine two voltages up to 60V or use them as dual voltage PS.
Pictures, details, schematic and PCB here.

[LEECH666]

Very nice. Is this the latest REV2 version of the PSU or the original version? The shematic seems to be different, and you're only using one output power transistor.

[audioguru]

Very nice. Is this the latest REV2 version of the PSU or the original version? The shematic seems to be different, and you're only using one output power transistor.

It is a combination of the original schematic and the latest schematic:
1) It uses Q2 to solve the "Opamp Phase Inversion" problem with the TL081 opamps used in the original project but the MC34071 opamps do not have that probem.
2) The value of R15 is much too high.
3) Its single 2N3055 output transistor will get extremely hot (maybe hot enough to fail) when the output is set for 3A and it is shorted or has a low voltage. Its max dissipation is about 90W.
It has a huge heatsink and a fan so maybe it will survive.

[xristost]

It is a combination of the original schematic and the latest schematic:
1) It uses Q2 to solve the "Opamp Phase Inversion" problem with the TL081 opamps used in the original project but the MC34071 opamps do not have that probem.
2) The value of R15 is much too high.
3) Its single 2N3055 output transistor will get extremely hot (maybe hot enough to fail) when the output is set for 3A and it is shorted or has a low voltage. Its max dissipation is about 90W.
It has a huge heatsink and a fan so maybe it will survive.

1) I deliberately kept Q2 because with it output voltage drop more quickly after power off.
2) R15 is 1k in original schematic and I don't know what will change if I replace it with lower value resistor since everything is working OK.
3) I decided to use only one output transistor, because the PS would rarely be used at low voltage and high amperage. With this heatsink and the fan running it manage to dissipate 60-70 W for a long periods without problem. For a couple of minutes it survived shorting at 3A.

BTW, for the second unit I put 2SC5589 instead of 2N3055, because it was ease to mount

[LEECH666]

I've got four TIP3055 (TO-218 / SOT 93) here, and two 2N3055 (TO-3). I've decided to use silent CPU coolers. I am uncertain if a single BD139 will be enough to drive four TIP3055s. I am only aiming for 30V / 3A output, so the additional TIP3055s would just be there to compensate for the lower power rating and to dissipate the heat more easily.

I have two options now ... (see attached pics):