24V 15A and 12V 5A voltage regulator design

[anboli]

Hi,

I having the toroidal transformer with dual secondary output voltage with following specifications,
Primary ==> 0-230Vac (50-60Hz)

Secondary ==> 0-30Vac 30Aac
==> 0-15Vac 5A ac

i need to design a voltage regulator for both the secondary outputs. My output voltages in 24Vdc 15Amps dc and 12Vdc 5Amps dc... Kindly help me, how to design it. If anybody having the sample circuit please update it.

thank you in advance.
anboli...

 

[tpetar]

Higher power switching voltage regulators such as:

LT3741EFE#PBF - DC-DC converter, Step-down; Uin:6÷36V; Uout:4÷34V; 20A
https://www.tme.eu/en/details/lt374...dc-circuits/linear-technology/lt3741efe_pbf/#

LT3800EFE#PBF - DC-DC converter, Step-down; Uin:4÷60V; Uout:1.23÷36V; 15A
https://www.tme.eu/en/details/lt380...dc-circuits/linear-technology/lt3800efe_pbf/#

.
.
.





Best regards,
Peter

 

[anboli]

Higher power switching voltage regulators such as:

LT3741EFE#PBF - DC-DC converter, Step-down; Uin:6÷36V; Uout:4÷34V; 20A
https://www.tme.eu/en/details/lt374...dc-circuits/linear-technology/lt3741efe_pbf/#

LT3800EFE#PBF - DC-DC converter, Step-down; Uin:4÷60V; Uout:1.23÷36V; 15A
https://www.tme.eu/en/details/lt380...dc-circuits/linear-technology/lt3800efe_pbf/#

.
.
.





Best regards,
Peter

hi peter,

I checked the datasheet of LT3800, from that we could get the output upto 36V and high current. but in their datasheets i saw all the typical applications circuits, in that all of them having either high volt with low current or vice versa. I cant get the 24v with 15A circuit. Could you tell me how to modify the circuit with their applications circuits. and if you know any other circuit please suggest me. because im not that much strong in the analog circuits and design.

i updated one of the circuit from the datasheet...

thanks in advance....
regards,
anboli....

 

[tpetar]

LT3800 datasheet
http://cds.linear.com/docs/en/datasheet/3800fc.pdf

See page 15, "Output Voltage Programming".

Output voltage is programmed through a resistor feedback network to VFB (Pin 6) on the LT3800. This pin is the inverting input of the error amplifier, which is internally referenced to 1.231V. The divider is ratioed to provide 1.231V at the VFB pin when the output is at its desired value. The output voltage is thus set following the relation:

R2 = R1 x (Vout/1,231-1)



Best regards,
Peter

 

[kam1787]

you might have trouble getting the 12VDC at 5A continuously from the transformer as it is at the maximum secondary winding current

 

[anboli]

LT3800 datasheet
http://cds.linear.com/docs/en/datasheet/3800fc.pdf

See page 15, "Output Voltage Programming".

Output voltage is programmed through a resistor feedback network to VFB (Pin 6) on the LT3800. This pin is the inverting input of the error amplifier, which is internally referenced to 1.231V. The divider is ratioed to provide 1.231V at the VFB pin when the output is at its desired value. The output voltage is thus set following the relation:

R2 = R1 x (Vout/1,231-1)



Best regards,
Peter

ya i got your point peter, by changing this two resistor value we could get the desired output? by this calculation, if i give R2 = 100K and R1 = 4.7K means i getting the Vout = 27.422V(Theoritically)..

what about the current? how to calculate for the desired current as like a voltage?