Timeline for Trying to regulate 24V from 24-30V 3A input
Current License: CC BY-SA 3.0
12 events
when toggle format | what | by | license | comment | |
---|---|---|---|---|---|
Apr 21, 2017 at 23:32 | vote | accept | Alian4life | ||
Mar 21, 2017 at 21:58 | answer | added | WhatRoughBeast | timeline score: 1 | |
Mar 21, 2017 at 20:37 | answer | added | bobflux | timeline score: 2 | |
Mar 21, 2017 at 20:11 | answer | added | StainlessSteelRat | timeline score: 0 | |
Mar 21, 2017 at 19:15 | comment | added | Rohat Kılıç | Yes, it's possible. You can use 2 or more LM338s connected in parallel. But you may need a huge heatsink for each. | |
Mar 21, 2017 at 18:52 | comment | added | Alian4life | Thanks for correction. So it seems like I would definitely need a converter. Can't I parallel 2*24V 1.5A regulators and some heatsink on them for that half amount of heat to take care of? | |
Mar 21, 2017 at 18:30 | comment | added | Rohat Kılıç | +1 for StainlessSteelRat 's answer. Just to correct your calculation: Junction-to-Ambient thermal resistance, \$R_{th(j-a)}\$, is more meaningful because it gives you directly the felt temperature of the heating element. Assuming the device has TO-220 package, total temperature rise will be \$\Delta T = (V_i-V_o) \cdot I_{LOAD} \cdot R_{th(j-a)} = 6V \cdot 3A \cdot 22.9°C/W = 412°C\$ and the felt temperature is \$T_f = \Delta T + T_{amb} = 436°C\$. Of course this is too much. Go for a DC/DC converter or, as SSR stated, decrease the input voltage. | |
Mar 21, 2017 at 18:15 | comment | added | StainlessSteelRat | 18W * 22.9 = 412.2 deg Celsius and maximum = 260. Junction to ambient. Add ambient temperature. Decrease voltage to 27V. 3V means 1/2 of load, so it will work. Load dissipation is not part of calculation. Personally, I'd go with a DC/DC convertor. | |
Mar 21, 2017 at 18:12 | history | edited | Alian4life | CC BY-SA 3.0 |
added 302 characters in body
|
Mar 21, 2017 at 18:09 | comment | added | Alian4life | It was TO220 but power dissipation was so high that it shuts down automatically | |
Mar 21, 2017 at 17:49 | comment | added | StainlessSteelRat | Was LM338 TO3 or TO220? Input-to-output voltage differential is a minimum of 3V. So you'd need 27V minimum for the regulator to work. | |
Mar 21, 2017 at 17:44 | history | asked | Alian4life | CC BY-SA 3.0 |