I'm glad that you already found the solution. I would have pointed you to that same formula.
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| -7,8V to -12V (MC34063) http://forum.lcdinfo.com/viewtopic.php?f=6&t=140 |
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| Author: | Guest [ Fri Feb 14, 2003 17:50 ] |
| Post subject: | -7,8V to -12V (MC34063) |
Hello! I have the Sharp LM24014 Display! The LCD needs -12V. If I use the circuits with the MC34063 form http://www.skippari.net/lcd/t6963c_schem.html I get -7,8V. Does anybody to wich value i must change the 5,6KOhm and 27kOhm to get -12V? Thanks. Bye Wolfgang |
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| Author: | Marty [ Fri Feb 14, 2003 22:37 ] |
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Are you going to try and actually make this? The charge pump device is quite exensive. There are other easier was to do this. Your computer PSU has -12v for example. Or you could use the transformer idea http://www.skippari.net/phpBB2/viewtopic.php?t=19 Marty |
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| Author: | Guest [ Sat Feb 15, 2003 2:44 ] |
| Post subject: | |
Marty wrote: Are you going to try and actually make this? The charge pump device is quite exensive. There are other easier was to do this.
Your computer PSU has -12v for example. Or you could use the transformer idea http://www.skippari.net/phpBB2/viewtopic.php?t=19 Marty I built it. The MC34063 is ca. 0,5€. But I found a solution. In this document: http://www.onsemi.com/pub/Collateral/MC34063A-D.PDF I change the Rs by this formula |Vout| = 1.25 * ( 1+ R1/R2 ) to R1=127KOhm and R2=16,2KOhm. And now the LCD works fine. Bye Wolfgang |
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| Author: | Henri [ Sat Feb 15, 2003 11:50 ] |
| Post subject: | |
I'm glad that you already found the solution. I would have pointed you to that same formula.
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| Author: | Götz [ Thu Feb 27, 2003 12:01 ] |
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Anonymous wrote: And now the LCD works fine. too late, but for others http://www.nomad.ee/micros/mc34063a/index.shtml online design tool for mc34063 as step-up, step-down, or inverting Götz |
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| Author: | Henri [ Thu Feb 27, 2003 13:17 ] |
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Götz wrote:
Nice one. Thanks for the link Götz. |
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