dc 24v to dc 12v circuit diagram

i want a dc 24v to dc 12 v powersupply. for a 12v power amplifier from a 24 v battery supply in vehicle.

use simple resistor divider network with 1:2 ratio. u'll have to use very high wattage resistors, (depending on current required). or use 12 regulator of current rating as required by u.

i need a circuit diagram pls

Originally Posted by prasanth9255

i want a dc 24v to dc 12 v powersupply. for a 12v power amplifier from a 24 v battery supply in vehicle.

How much output current do you require?

If you need <1A then you can use LM7812 voltage regulator, if you need more current you will need to add an external power transistor (with a heatsink) .. see picture below ..

More details you can find at:
http://www.southwest.com.au/~jfuller...regulators.htm

Regards,
IanP

save yourself time and effort

connect your unit to lower battery through a suitable fuse
and give yourself a high current low impeadance 12V--Chassis supply.

Polymath

It could be possible using a DC-DC converter(switching mode) it can supply high current with very high efficency and usually it doesn't need heatsink. Try to see Tracopower devices. I can't suggest you a specific IC but i know there are a lot of small DC DC integrated converter for low current. You have to search for 'step down' converter for example in Linear technology or Maxim sites.

prasanth9255

state what current you require
does your amp require exactly 12V or is it suited to 12V vehicles (8-16V)?

Does it have its own switching psu built in?
- as normally used in high power low supply voltage amps (eg. to boost +12Vnom to +/-30v)

- if so you may get interaction problems (between switching frequencies) if you use a switch mode psu to drop the 24v to 12v

- mixing switch mode psus in series is not normally recommended.

regards Polymath

Dear,

You Can use LT1083 Series regulators from Linear Technology.They Can provide

up to 7A.(3 & 5 Amp Regulators are also available).

for Lower Power Dissipation you can use a switching regulator.L296 from ST

(SGS-Thomson,www.st.com)can Provide you up to 4A.

Good Luck.

the attached circuit diagram for 24v dc to 12v dc, can i still use it for my 19v dc output by only changing the LM7812 to LM7818 or LM7819, for example. what of the values of the resistor. my load current is 3A.

Any buck converter will be an ideal solution for your problem.

the source being battery in vehical, you should save the battery power, i mean, you can use resistor divider but it will draw some current. further you have to connect voltage regulator 78xx which will descipate additional power leading to faster drain of battery. instead you can use a non-isolated buck converter which has higher efficiency than linear volatge regulator.

pls can someone help me with a schematic circuit diagram for converting a 24v dc to 19v dc regulator supply.

Originally Posted by snazzy c

pls can someone help me with a schematic circuit diagram for converting a 24v dc to 19v dc regulator supply.

Hi,

check LM2576 Datasheet : http://www.national.com/ds.cgi/LM/LM2576.pdf @ Page 10 you can see the Adjustable Version of LM2567 configuration (your input voltage is 24v , you can use regular version of LM2576-adj not LM2576HV-adj) change the R1 & R2 Values to give you 19v Output. it's a 3A Regulator. USE R1=1K , R2=8.6K+10K(POT) and adjust output voltage with the 10K POT.

for an easier config : download LT1083/10804/1085 Datasheet : http://cds.linear.com/docs/Datasheet/108345fg.pdf and @ Page 11 check the circuit. use : R1=120 & R2=1K+2K(POT) . adjust output voltage with the POT. Remember LT1083 is a 7.5A regulator , LT1084 is 5A Version and LT1085 is 3A Version. and if you are willing to use Linear Regulators Like these regulators for high Current you should have a Very good Heat-Sink. For Example : if you want to use these regulators for 3A , your regulator will Dissipate 15W. >> (Vin-Vout)*I=Pd >> Pd=(24-19)*3=15W , so you need a good heat-sink. you won't have this problem with the switching regulator (LM2676) at this rate (but it will need the heat-sink too , but for lower dissipation. for example around 3W~4W.)

You can use MC34063 switching regulator http://www.onsemi.com/pub_link/Colla...MC34063A-D.PDF , can provide up to 1.5A

Use this tool MC34063A design tool to calculate the needed component values.

Alex