Resistors values for LT1074 buck converter

[jmx66]

Hi all,

I only want to get resistor values R3, R4 and R5, to get 16V and ≈ 2A output.

In fact, i'd like to know how to compute them, as schematics found were with Common emitter, Base and so on, so with power supply between Base and Emitter by example.

In this schematic, Base is linked to ground ??



View attachment AN44-LT1074-Design-Manual.pdf

Thanks a lot.

jm

 

[D.A.(Tony)Stewart]

The app note defines the requirements.
"The voltage across R4 is set at 1.1V by R3, which is connected to the output"

ILIM = Desired output current limit. ILIM should be set ≈1.25 times maximum load current to allow for variations in VBE and component tolerances.


RS=(R4*IX +VBE)/( ILIM/100–IX)

IX = VOUT + VBE + 0.4mA

I didn't go beyond this. good luck

 

[jmx66]

Hi SunnySkyguy,

Thanks a lot for your reply, in fact i found it also in datasheet, but thought there was other stuff .... It seemed me too simple.

Now i can end my spreadsheet with this reply :grin::grin:

You are right: LDO regulators and smps are muuuuch more efficient:smile::smile: than linear :---(

Regards.


jm