Author Topic: Lahat ng questions related sa Switched-Mode Power Supply (SMPS) (Read 76965 times)

drin20 · « **Reply #1080 on:** June 17, 2012, 06:01:32 PM »

hello!
para saan po ung OCP at OCP-G?
sa feedback po simpleng voltage diver lang naman un diba?

pwedi po ba gawin itong 330vdc?
modify ko na lang ang turn ratio ng transfo?

edit: pinalaki ang imahe

Philippine Electronics Forum · « **Reply #1080 on:** June 17, 2012, 06:01:32 PM »

j a y k e z · « **Reply #1081 on:** June 17, 2012, 06:20:27 PM »

di ba OCP stands for Over Current Protection?

Philippine Electronics Forum · « **Reply #1081 on:** June 17, 2012, 06:20:27 PM »

motion55 · « **Reply #1082 on:** June 17, 2012, 06:29:22 PM »

OCP = Over-Current Protection ata. Hindi complete ang view ng schematic kasi.

Here is my analysis:

Pag ang voltage sa OCP-P (positive) ay tumas w.r.t. OCP-G (ground), then mag ON si C945 and also turning ON A1015. This will shutdown uPC494 through pin 4. At the same time, the transistor C945 will remain ON (latched like an SCR) until power is turned OFF.

Philippine Electronics Forum · « **Reply #1082 on:** June 17, 2012, 06:29:22 PM »

drin20 · « **Reply #1083 on:** June 17, 2012, 06:52:14 PM »

Quote from: motion55 on June 17, 2012, 06:29:22 PM

OCP = Over-Current Protection ata. Hindi complete ang view ng schematic kasi.

Here is my analysis:

Pag ang voltage sa OCP-P (positive) ay tumas w.r.t. OCP-G (ground), then mag ON si C945 and also turning ON A1015. This will shutdown uPC494 through pin 4. At the same time, the transistor C945 will remain ON (latched like an SCR) until power is turned OFF.

salamat sis.

pwedi pala naka hung lang yon.

Philippine Electronics Forum · « **Reply #1083 on:** June 17, 2012, 06:52:14 PM »

Pinoy_Tech · « **Reply #1084 on:** June 17, 2012, 11:48:35 PM »

Tama sila pareho at tama ka rin kahit walang connection yung ocp pwede pa rin, yun nga lang wala ka ng margin for safety. Pwede kang kumuha ng current sensing sa source ng mosfet, mag add lang ng resistor na low value like used in yamaha smps or yung small toroid core na nakakatay sa pc psu.

Kung gagamitin mo yung trafo ng pc psu, yung output mo is almost closed to what you need.

Philippine Electronics Forum · « **Reply #1084 on:** June 17, 2012, 11:48:35 PM »

_basura_man() · « **Reply #1085 on:** June 18, 2012, 08:28:28 AM »

actually yung OCP pwedeng up to 120% ng full load current

drin20 · « **Reply #1086 on:** June 19, 2012, 12:15:22 AM »

salamat po sa inyo

eto pa po tanong ko.

para saan po ang R5 at R7?

hindi ko maintindihan lalo na ung R5. bakit pa kailangan un? edi mababawasan lang ang voltage from Vref after ng dividing network.

rdpzycho · « **Reply #1087 on:** June 19, 2012, 12:59:03 AM »

pang-set ng gain nung opamp. EA gain = R7 / R5 = 100. typically, linalagyan pa 'yan ng compensating capacitors depende sa topology at actual values ng LC filter.

♪ ♫ ♫ ♪ ♪ ♪ ♫ ♫ ♫ · « **Reply #1088 on:** June 19, 2012, 08:36:29 AM »

may nag-alok sa akin na gumawa ng portable 125Vdc, 10A na smps psu, i want to pass this project to anyone who wants to make it. the budget could be as hi as php 20k - 30k. wala nalang akong time akong time may pending pa kasi akong dalawang electrical projects and i am currently working with this 1 to 2 months project, kaya gusto ko nang itong ipasa sa iba.

anyone who wants it, just pm me.

drin20 · « **Reply #1089 on:** June 19, 2012, 06:26:33 PM »

Quote from: rdpzycho on June 19, 2012, 12:59:03 AM

pang-set ng gain nung opamp. EA gain = R7 / R5 = 100. typically, linalagyan pa 'yan ng compensating capacitors depende sa topology at actual values ng LC filter.

salamat sir Rdpzycho
kaya pala meron non-polar capacitor sa design ni Pinoy Tech.

EA gain = 1 + (R7/R5) = 101

drin20 · « **Reply #1090 on:** June 26, 2012, 02:55:21 PM »

una 400 and output tapos biglang tataas ng 600 VAC. wala pa po rectifier at load.

gamit ko core, power mosfet, ay sa nakatay ko APC ES-500

kabit ko meya ung rectifier na MUR460 na galing din sa UPS ng APC.

may klase na kasi kami. hehehe.

thanks po sa inyo. sir RD, sir motion, sir jikkks, sir Rafft, at sir Pinoy_tech

RaffT · « **Reply #1091 on:** June 26, 2012, 03:00:51 PM »

400Vdc pala ang rectified output? pwede ka naman mag lagay ng 2u2/400V elcap sa output, then sukat ulit para mas stable ang reading.

drin20 · « **Reply #1092 on:** June 26, 2012, 03:05:48 PM »

400 vac po una output. after 2 seconds biglang tataas ng 600 vac. meya ko ikabit ang rectifier at caps.

kailangan ko din pala ng pot para sa feedback.

j a y k e z · « **Reply #1093 on:** June 26, 2012, 03:11:22 PM »

wow nice sis, abangan ko toh

ayos mini molex connector as transistor pin connector

Disabled · « **Reply #1094 on:** June 26, 2012, 03:23:58 PM »

makagawa na nga nito.

RaffT · « **Reply #1095 on:** June 26, 2012, 03:26:53 PM »

teka, paanong naging AC? DC ang output nyan, hindi AC

baka tumataas output nyan kasi wala ka nilagay na voltage feedback..delicado yan pag nag lagay ka caps sa output

Pinoy_Tech · « **Reply #1096 on:** June 26, 2012, 09:23:17 PM »

Wala pa raw syang diode na naka kabit sa output kaya AC daw. He read the output without rectifier pero medyo false reading pa yun kasi high F. Pag na DC na yun na yung ma read an actual then compute sa given data na 1.41 or 0.707. Either of the two pwede. Yung isa divide sa nasukat na dC, yung isa naman times o baka nakalimutan ko na, kulang na sa tagay he he, hik!

Disabled · « **Reply #1097 on:** June 26, 2012, 09:40:14 PM »

last year, sir tony gave me mur860 diodes . looks like this

pde po ba to sa output side?

Disabled · « **Reply #1098 on:** June 26, 2012, 10:13:53 PM »

deleted

Pinoy_Tech · « **Reply #1099 on:** June 27, 2012, 05:36:26 AM »

MUR? Wow! Pwede yan pero sayang naamn kung low voltage lang ang paggagamitan.

San kaya nabili ni sir Tony yang ganyang diode? Nilibot ko na yung Raon last
month pero wala akong matyempuhang ganyang type. MUR810 lang tested na
ng marami sa +/-50VDC application.

Philippine Electronics Forum · « **Reply #1099 on:** June 27, 2012, 05:36:26 AM »

Author Topic: Lahat ng questions related sa Switched-Mode Power Supply (SMPS) (Read 76965 times)

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