Electronics > Beginners
Review my Schematic
redgear:
I have been trying to recreate a schematic from a Chinese datasheet. Can someone please review it?
Here is the picture of the connections as given in the datasheet:
The VSN,VSYS and VSP pins are shorted on the first diagram. I have followed the same and connected them together.
Here is my schematic:
1) The IP5328P is a custom symbol created by me, when I connect a Label to the pins it creates a junction but no junction is created for single connection on pins in the USB ports(kicad default symbols). Is that a problem? Did I make a mistake while creating the symbol?
2) Are the Gate, Drain and Source pins of the MOSFETs Q1 and Q2 properly connected.
3) They have used a Electrolytic Cap for C15 and chip capacitors(i guess they referring to SMD) for all others. Can I use the same? Will any SMD cap should be fine for others?
4) The pins VSYS,VSN and VSP are connected together. I have tried to follow the the diagram on top of the datasheet, have I done that correct?
5) Do I really need a 220uF 25v capacitor on the C15? Many powerbanks using the IP5328P does not use any Electrolytic cap at all and the ones that use have them rated at 100uF 16V.
http://bbs.chongdiantou.com/data/attachment/forum/201909/29/095355uyh41te7nfpvyh1x.jpg
http://bbs.chongdiantou.com/data/attachment/forum/201811/08/180416m6kzrpcb8mp43i49.jpg
http://bbs.chongdiantou.com/data/attachment/forum/201910/15/141137n02444z4lvr97mk3.jpg
http://bbs.chongdiantou.com/data/attachment/forum/201901/09/220736y17r7c7c9ts7z3l3.jpg
This one uses a 220uF 16v capacitor:
http://bbs.chongdiantou.com/data/attachment/forum/201909/03/112541yz4auqu4ohzav494.jpg
I am also attaching the PDF versions of the Datasheet and Schematic
Thanks
Gallardo:
-->1, Kicad I have no use, but from the picture point of view, there is no real connection on the USB port, you need to check the package, or pin properties.
--> 2, is the correct connection.
-->3, in this circuit, the main function of the electrolytic capacitor is energy storage, and the chip capacitor is mainly to suppress noise. If you are not familiar, I think it can be designed according to official advice.
--> 4, is correct.
-->5, I recommend using the official instructions to use the components, after all, the official is the BOM obtained through various electrical performance tests; because the 200uF/25v capacitor is bulky, it is not conducive to controlling the thickness of the product, so it will be smaller Point solution capacitors to meet product structure requirements. Some use 16v capacitors (USB output maximum voltage is 12v), or not used, I believe more to save costs, which I think is not very rigorous. Even if I am Chinese.
redgear:
--- Quote from: Gallardo on November 09, 2019, 05:56:33 am ----->1, Kicad I have no use, but from the picture point of view, there is no real connection on the USB port, you need to check the package, or pin properties.
--> 2, is the correct connection.
-->3, in this circuit, the main function of the electrolytic capacitor is energy storage, and the chip capacitor is mainly to suppress noise. If you are not familiar, I think it can be designed according to official advice.
--> 4, is correct.
-->5, I recommend using the official instructions to use the components, after all, the official is the BOM obtained through various electrical performance tests; because the 200uF/25v capacitor is bulky, it is not conducive to controlling the thickness of the product, so it will be smaller Point solution capacitors to meet product structure requirements. Some use 16v capacitors (USB output maximum voltage is 12v), or not used, I believe more to save costs, which I think is not very rigorous. Even if I am Chinese.
--- End quote ---
Thanks a lot for your reply! I appreciate it.
jhpadjustable:
0. Proofread your images before posting. 4px high text is not a good way to attract volunteers. :)
1. There should NOT be a junction at the pin if only one wire is connected. Your symbol pins are probably off-grid. In particular, check the symbol pin length and make sure it's a multiple of the schematic grid, or better yet, the same length as other pins of similar symbols.
2-5. What Gallardo said, nothing to add.
5. Adding, and keeping in mind the high-volume commodity nature of the intended application, the 220µF electrolytic is probably oversized in order to meet ripple current and ESR limits without going to a specifically low-ESR, high-ripple, or high-frequency electrolytic.
redgear:
--- Quote from: jhpadjustable on November 09, 2019, 06:11:17 am ---0. Proofread your images before posting. 4px high text is not a good way to attract volunteers. :)
--- End quote ---
Sorry, but it was the best picture I got. That's why I included the actual datasheet in the attachments.
--- Quote ---1. There should NOT be a junction at the pin if only one wire is connected. Your symbol pins are probably off-grid. In particular, check the symbol pin length and make sure it's a multiple of the schematic grid, or better yet, the same length as other pins of similar symbols.
--- End quote ---
KiCad threw a warning that my pin lengths are not multiples of the schematic grid, looks like that's the mistake I did. Thanks.
--- Quote ---5. Adding, and keeping in mind the high-volume commodity nature of the intended application, the 220µF electrolytic is probably oversized in order to meet ripple current and ESR limits without going to a specifically low-ESR, high-ripple, or high-frequency electrolytic.
--- End quote ---
So, I can either use the oversized capacitor or pick a low ESR and a higher ripple current. Since the latter would cost more $$ they have used a oversized capacitor in the design, Correct?
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