questions on a schematic - Page 1
Forum section: electronics / beginners

author: redgear
author_rank: Frequent Contributor
timestamp: November 05, 2019, 07:40:57 am
content: The above schematic shows pin 24(VSP) as shorted with pin 23(VSYS4) and pin 22(VSYS3). Is that correct?In the other side, only capacitor CP12 is shown as a polarized capacitor but the other capacitors also seem to use the naming convention as a polarized capacitor(CPxx). Is that a mistake or all capacitors polarized?Thanks

author: PA0PBZ
author_rank: Super Contributor
timestamp: November 05, 2019, 08:11:51 am
content: Quote from: redgear on November 05, 2019, 07:40:57 amNo, they are just crossing on the diagram.QuoteThey should all be polarized.

author: magic
author_rank: Super Contributor
timestamp: November 05, 2019, 08:17:44 am
content: Quote from: redgear on November 05, 2019, 07:40:57 amBy usual convention, if there is no dot where the lines intersect, they aren't connected. Although it doesn't preclude mistakes or people trying to be creative.I would say that VSN and VSP are each connected only to one capacitor and VSYS3 and VSYS4 are separate too.What is this device supposed to be and do?Quote from: redgear on November 05, 2019, 07:40:57 amPerhaps a mistake, perhaps they meant an MLCC. I'm not sure what's the state of the art but 22µF/25V isn't far from values I know are possible.

author: redgear
author_rank: Frequent Contributor
timestamp: November 05, 2019, 08:30:39 am
content: Quote from: PA0PBZ on November 05, 2019, 08:11:51 amThanks...There are more capacitors with a unpolarized symbol having the name CPxx. Should they all be polarized? I am attaching the entire circuit below.Quote from: magic on November 05, 2019, 08:17:44 amThis a Powerbank SOC. It identifies and controls the fast charging protocols. The name of the IC isIP5328P

author: JackJones
author_rank: Regular Contributor
timestamp: November 05, 2019, 08:39:30 am
content: It isn't very clearly drawn, but there is another example schematic right at the top of the datasheet. On that it seems all the VSYS pins and VSP are connected together.The VSYS pins are commoned in the example you posted as well, they are just using a global label to do so. So not very clearly drawn again.

author: PA0PBZ
author_rank: Super Contributor
timestamp: November 05, 2019, 08:41:08 am
content: In the datasheet they say that CP4,5,6 and 11 are "chip capacitors" and CP12 is an "electrolytic capacitor, so maybe MLCC after all although electrolytic would do a fine job there too in my opinion.

author: redgear
author_rank: Frequent Contributor
timestamp: November 05, 2019, 09:01:58 am
content: Quote from: JackJones on November 05, 2019, 08:39:30 amJust checked the diagram on top of the datasheet. What can I do? Should I connect them together?Quote from: PA0PBZ on November 05, 2019, 08:41:08 amThanks... Will use a electrolytic cap there.I'm confused about the other connections.

author: JackJones
author_rank: Regular Contributor
timestamp: November 05, 2019, 09:17:35 am
content: Actually, there is a layout picture of that specific area. It does show that pins 22, 23 and 24 are indeed connected together.

author: iMo
author_rank: Super Contributor
timestamp: November 05, 2019, 09:22:47 am
content: All that capacitors are part of the Boost converter together with L1=2.2uH (based on the schematics in DS). So rather small ESR there is required, therefore many in parallel.I would rather stay with 22uF MLCC there.

author: PA0PBZ
author_rank: Super Contributor
timestamp: November 05, 2019, 09:25:45 am
content: Quote from: JackJones on November 05, 2019, 09:17:35 amYes, I stand corrected, this is one of the worst drawn schematics I've ever seen, you should never cross connections like that if they are connected but do something like this:Code:___||___|

author: JackJones
author_rank: Regular Contributor
timestamp: November 05, 2019, 09:37:19 am
content: Combine that with different thickness used for the traces it is definitely confusing. (though I like the idea of identifying high current traces like that) If there was a dot to mark a connection it would be much clearer.They even used the exact replica of the pinout of the chip to make the schematic, rather than arranging it nicely to make it clear. Compare it with the example schematic at the top of the datasheet where everything is arranged neatly and is easy to read.

author: redgear
author_rank: Frequent Contributor
timestamp: November 05, 2019, 09:42:56 am
content: Thank You everyone. I will post the schematic once I complete it. Would be great if you guys can review it.

author: soldar
author_rank: Super Contributor
timestamp: November 05, 2019, 01:33:00 pm
content: For schematics I like a blob of Sn solder if they are connected and a sort of "shadow" if they are not connected. I think this avoids confusion.If it is not a crossing but just a T then there is no doubt they are connected.

author: redgear
author_rank: Frequent Contributor
timestamp: November 06, 2019, 08:19:46 am
content: I'm attaching the schematic I created and the datasheet. Can someone please review it?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). Did I make a mistake while creating the symbol?2) I hope the Gate, Drain and Source pins of the MOSFETs are properly connected.3) They have used a Electrolytic Cap for C15. 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?

author: redgear
author_rank: Frequent Contributor
timestamp: November 06, 2019, 11:21:08 am
content: 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.jpghttp://bbs.chongdiantou.com/data/attachment/forum/201811/08/180416m6kzrpcb8mp43i49.jpghttp://bbs.chongdiantou.com/data/attachment/forum/201910/15/141137n02444z4lvr97mk3.jpghttp://bbs.chongdiantou.com/data/attachment/forum/201901/09/220736y17r7c7c9ts7z3l3.jpgThis one uses a 220uF 16v capacitor:http://bbs.chongdiantou.com/data/attachment/forum/201909/03/112541yz4auqu4ohzav494.jpg