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In Reply to: RE: LiFePo4 Battery from 13.2V to 12V (or 11.8V) posted by jackwong96 on November 27, 2011 at 03:50:12
Any 3-pin LDO regulator suggested?
I also want to use a capacitor bank (http://www.ebay.com.hk/itm/220899802413?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_1522wt_901) and the diodes will be replaced by 2 wires.
Therefore:-
LiFePo4 battery 13.2V --> capacitor bank --> LDO regulator (Belleson?) --> CPU (P4)
LiFePo4 battery 13.2V --> capacitor bank --> LDO regulator (Belleson?) --> pico-PSU --> MoBo (P24)
I will report whether SQ will improve as compared to Linear PSU.
P.S. my LiFePo4 battery is bought in China.
Follow Ups:
LiFePo4 has very low internal resistance, in mohm, so only very high speed small cap can help them further. The caps on the ebay link do not appear to be high grade ones, I don't think they'll help. LiFePo4 is alread the best choice.
If you want to improve SQ, invest on the 5V rail which is in the audio chain and thus most critical. P4 12V powers the CPU core and graphic etc and has a secondary role. The CPU core is somewhat like the engine of a car but the ram and I/O circut are like a ECU (the brain) which programs and direct how the engine will run.
LDO ICs with 3A or more current delivery capability, such as LT1084, 1085 & 1086 can do the job. You may try using high quality regulators, but I don't know whether they will improve SQ. Please give it a try, as I want to know the result.
Hi Jack,
I also live in Hong Kong and also a civil servant!!! What a coincidence!!!
May I e-mail you asking more questions about Computer Audio?
Yes. No problem. For general questions about CPLAY/CMP/Computer do share in this forum so that everyone will benefit. We can go out for tea and have a discussion, you might have seen me before!
Small cap!? You are right as core audio also suggests so: http://www.coreaudiotechnology.com/blog/?p=24.
Therefore, I should use Oscon. What value (Voltage and Farads) should I use?
Is this one OK: http://www.ebay.com.hk/itm/68Pcs-220uF-63V-korea-cap-Power-supply-board-kit-sc-/200619648046?pt=LH_DefaultDomain_0&hash=item2eb5dce42e#ht_2354wt_901? I can replace all cap with Oscon!!!
Oscon is not good enough, I recommend Siemens Sikorel. 100-220uf 16V will do the job, bypassed by 0.1uf MKP cap.I recommend buying from Taobao.com rather than Ebay, cheaper.
The source.
http://search.taobao.com/search?q=sikorel&searcy_type=item&s_from=newHeader&source=store&ssid=s5-e&search=y
Edits: 11/27/11
Thank you, Jack.
I understand that the cap should be connected in parallel. How many pieces do I need?
How should I connect the bypass cap? Should I also connect it in parallel but closest to the load?
Regards
Battery supply is quite pure and has no ripple. Hence big caps are not necessary. They have noise however. The small caps are for absorbing battery noise and enhancing high frequency response. Therefore, quality rather than quantity matters. 100-220uf + 0.1uf will be fine. I used 22uf 63V Sikorel, just happen to have such value and they work fine.
One suggestion is to connect the caps to the bottom of the Mobo, and in this, beneath the P4 12V socket.
See link.
http://www.audioasylum.com/forums/pcaudio/messages/7/75904.html
Thank you, Jack.
I now decide to connect in the following way:
LiFePo4 (13.2V) --> 1.5R, 5W resistor in series (later change to Caddock) --> 220uF 16V cap (later change to Simens SIKOREL125) in parallel --> 0.1uF cap (later change to MCap) in parallel --> CPU (P4)
I try to avoid using any IC in the circuit as far as possible.
I have seen your mod on the mobo. Wow, great great work!!! I also wish to have my mobo mod like yours!!! I now use gigabyte 890GPA-UDH3 which is a AMD system as AMD has a lower SMI latency value.
Thank you for the advice again.
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