I have designed my first PCB using the IP5306 power management IC, based closely on the reference schematic provided in the datasheet.
Since this is my first design involving a switching power supply and inductor-based circuit, I would really appreciate feedback from experienced designers on any potential mistakes or layout issues.
I designed the PCB using EasyEDA Pro, and the schematic is embedded within the project. For some reason, I was unable to upload the .epro file directly here, so I’ve shared it via a Google Drive link instead.
What is the function of key1 ?
Do you want the 3v3 circuit permanently across the output ? Could it possibly be detected as a load and keep the boost converter running all the time. It is the same with some of those indicator leds which could present an unwanted load.
The original circuit appears to have been designed for USB-A sockets on the output and you have changed that to USB-C. It was simple with USB-A which were 5v output only. Maybe you need some protection against potential backfeeding through the USB-C on the output side.
Its for turning the Boost Converter on and off.
I don't want 3v3 permanently, doesn't the IP5306 turn off the Boost when there is no load detected. I placed those indicator LEDs just for easy debugging, to know if the current is flowing.
Can you please suggest how to protect against the back feeding in USB-C is a diode in series with VBUS enough?
Your link brings me to the root of your project.
Pretty unclear whete to find the pcb layout.
I suggest to save as .png or .pfd or something else and then upload to the forum....(no goohle drive links).
Actually, first I thought of making a breadboard power supply which later turned into a Power Bank which can also function as a Breadboard power supply. So I wanted to keep the 3.3v power in case if I had to power something that's 3.3v sensitive.
but not on the schematic.
Any part that is on the PCB must be shown on the schematic, otherwise you may have problems later on with the BOM and footprints.
From the IP5306 data sheet it was not clear to me whether the push button switch was intended for the "Built-in lighting drive" function which looks like support for a sort of built in flash light device. If you retain the button and omit the led (D5 in data sheet) then I guess it would serve start the device.
It also wasn't clear to me if the quiescent current of the TLV6256x buck converter would keep the IP5308 in active mode all the time but I've now seen that that current is of the order of 50uA (without the additional LED) which should allow the IP5306 to drop into standby mode if the buck has no load.
That would certainly work at the expense of a 0.3v Schottky diode drop. I've tried to find a reference schematic, that is a powerbank with USB-C as an output, and the best I can find is here near the end in chapter 8 (page 23). INJOINIC-IP5328.pdf (2.4 MB)
There the solution is to use a PMOS which is switched by the controller chip. The chip you are using does not have that option directly.
I have incidentally an Xiaomi powerbank which has a USB-C socket which can serve as both an input and an output. I do wonder what would happen if I connected it via that socket to an identical power bank. Somehow they would have to negotiate between them which was charging and which was being charged ! It is even more complicated because it supports USB Power Delivery and miscellaneous other adaptive protocols. Unfortunately, I have no schematic for it.
I can't see the board layout but in principle keep the inductor close to the output capacitor(s) and well away from the any feedback circuit.
So, unless I plug my output USB-C Connector to a USB Source device its fine?
Here are the screenshots of my PCB. If you want to have a deeper look please use EasyEDA Pro (I dont know how to use KiCad so I had to use EasyEDA, sorry for the inconvenience)
You can also access it through web https://pro.easyeda.com/editor.
