LM723 regulated power supply question

[Woots29]

questions,

1. Pwede ko bang palitan yung mga Q2 to Q5 ng PNP (TIP36) at gagawing Sziklai pair?

2. pwede ko bang palitan ng 2 transitor to form a darlington yung Q1?

salamat po

[glutnix_neo]

master bat parang di makita picture?

Icon ng tripod lang ang nakikita

[Woots29]

ulit, ulit xenxa

questions,

1. Pwede ko bang palitan yung mga Q2 to Q5 ng PNP (TIP36) at gagawing Sziklai pair?

2. pwede ko bang palitan ng 2 transitor to form a darlington yung Q1?

salamat po

[Woots29]

up

[zer0w1ng]

You can replace the NPN drivers with PNP this way:

Code: [Select]

              0.1ohms
-+-----E   C----R------+----
 |       B PNP Q2-Q5   |
 |       |             |
 |       |             |
 +--R----+---C   E-----+
  100ohms      B NPN Q1
               |
               |

No need to make it darlington.

[Woots29]

ayun confirmed.

salamat sis

[TinTopHack]

I recommend caution. While you can connect them as Zerowing has suggested you could have problems balancing the current through all PNP transistors because you no longer have the ballast resistors at the emitters. While you might be able to transfer the resistors - previously at the emitter of the NPN devices - to the emitter of the PNP devices your current limiting function in the LM723 will not work anymore. I am not saying that the Sziklai approach will not work. What I am saying is it will not be a matter of simple conversion to Sziklai. Additional work needs to be done.

[Woots29]

^so anu dapat gawin sir?

wel kelangan ko talaga ng PNP ang output (may nakalagay na TIP36 na dalwa sa aking pow supply)

may ckt ba kayu jan sir?

[zer0w1ng]

To maintain the current balancing, you could move the 0.1 ohm resistors to the emitter of the PNPs but the constant current protection may not work and needs a redesign as sir TTH stated.

[TinTopHack]

You might want to try this. But you need to review the LM723 data sheet so you can recalculate values of some components especially Rs and Rf

[Woots29]

+1 sir

question:

i have 2 PNP outputs, it is necessarily to replace the 0.1 with higher resistance?

[TinTopHack]

+1 sir

question:

i have 2 PNP outputs, it is necessarily to replace the 0.1 with higher resistance?

I think you can keep the value as is for now. Later kung gumagana na sya you can check how the full load current is divided between the 2 transistors. Kung malaki ang imbalance you could increase the value a bit.

[Woots29]

cge sir salamat ulit asemple ko muna