| General > General Technical Chat |
| 20vdc to usbc adapter |
| << < (2/2) |
| tom66:
In order to support USB-C, the device is almost certainly a buck-boost converter. This is because it needs to accept 12V in and output 5, 9V, 15V or 20V. That's two buck modes and two boost modes. So in the 24V mode it just operates in buck all the time. It's very likely to therefore work over a continuous range. These types of devices are pretty common nowadays, they use 4 transistors to transition between being a buck converter and a boost converter. Some older designs use a discrete buck followed by a discrete boost, but those are pretty uncommon nowadays. |
| waoj:
I was actually doing some reading on USB C PD. And there is something new called PPS (programmable power supply). I think it's the latest version of PD. And if supported/negotiated, the receiving device can ask for voltages in steps of 20mv. Imagine it making up for loss in the cable with that! I wish there was a usb tinker-er forum akin to eevblog but specific to usb. |
| David Hess:
--- Quote from: waoj on March 19, 2023, 05:20:00 pm ---Do you have one of these Lenovo adapters David, to test if it supports 19, 20, or 21v? (careful, it could break it) It looks like the car connector on it is easily removed and replaced with a barrel jack which would be nice as the automotive connector is rather fickle, and large to carry around. --- End quote --- I have one but my variable bench supply is only 1 amp so not suitable for a full power test. It would take 5+ amps to test its full input range. |
| ve7xen:
--- Quote from: NiHaoMike on March 16, 2023, 04:18:29 am ---I wonder if it could be done with a linear regulator for the initial 5V which is bypassed when 20V is requested. How much current does it take at 5V while it's requesting 20V? --- End quote --- Probably very little. But the hard part is implementing USB-PD, not the power supply. Modules do exist that take DC in and provide USB-PD out. Search AliExpress for SW3516, SW3518, SW3526 modules. I think this family is buck-only, so you need to supply >20V for 20V USB-PD. For more capability look for IP2368 modules, they generally have charging capability and it's buck-boost. There are probably more options than these. |
| NiHaoMike:
--- Quote from: ve7xen on March 23, 2023, 05:29:53 pm ---Probably very little. But the hard part is implementing USB-PD, not the power supply. Modules do exist that take DC in and provide USB-PD out. Search AliExpress for SW3516, SW3518, SW3526 modules. I think this family is buck-only, so you need to supply >20V for 20V USB-PD. For more capability look for IP2368 modules, they generally have charging capability and it's buck-boost. There are probably more options than these. --- End quote --- Would it be possible to bit bang USB-PD with a microcontroller? |
| Navigation |
| Message Index |
| Previous page |