Easy USB‑C Power For All Your Devices

April 21, 2021 by Anool Mahidharia 28 Comments

[Mansour Behabadi] wanted to harness the high power capability of USB-C using as simple a hardware design as possible. After some research and experimental prototyping, he designed the fpx — an easy to use USB‑C power delivery board. The fpx is an improved follow up to his earlier USB PD project fabpide2 which we featured some time back. However, practical implementation of the USB PD protocol can be a bed of thorns. Negotiating power delivery usually requires a dedicated PD controller coupled with a micro-controller for user control.

With USB PD, a USB-C port can be configured as either a source, a sink, or both and allows connected devices to negotiate up to 100 W (20 V, 5 A) of power. The fpx is based around the popular STUSB4500 PD controller, which does most of the PD heavy lifting. To program the STUSB4500, he used an ATtiny 816 micro-controller, whose UPDI programming and debugging interface consumes lower board real estate.

However, what’s a little bit different is the way the fpx is programmed — by sending binary black and white flashes from any device that can display a web page. Using light isn’t a particularly new way of programming. We’ve seen it used almost a decade back by WayneAndLayne for their Blinky PoV projects, and later by the Electric Imp’s BlinkUp app. The fpx uses a similar method to read flashes of light from a screen which are picked up by a photo-transistor connected to the ATtiny. The ATtiny then communicates with the STUSB4500 over I²C. This eliminates the requirement for special software or an IDE for programming and doesn’t need any physical cable connection. Check out [Mansour]’s blog post where he walks us through the details of how he managed to wrangle the optical programming challenge.

Many of the commercially available USB PD decoy/detector/trigger boards use either solder jumpers or a switch with an RGB LED to adjust Power Delivery Output (PDO). [Mansour]’s method may be a little more robust and reliable. The STUSB4500 can store two separate PDO values and can negotiate with a source according to its capability. If the source cannot offer either of these options, the fpx can either request for a minimal 5 V / 100 mA setting, or disable the output. The fpx is an open source project, accessible on Github. Check out the video after the break for an overview of the fpx.

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USB Power Delivery For All The Things

October 18, 2019 by Tom Nardi 25 Comments

The promise of USB Power Delivery (USB-PD) is that we’ll eventually be able to power all our gadgets, at least the ones that draw less than 100 watts anyway, with just one adapter. Considering most of us are the proud owners of a box filled with assorted AC/DC adapters in all shapes and sizes, it’s certainly a very appealing prospect. But [Mansour Behabadi] hasn’t exactly been thrilled with the rate at which his sundry electronic devices have been jumping on the USB-PD bandwagon, so he decided to do something about it.

[Mansour] wanted a simple way to charge his laptop (and anything else he could think of) with USB-PD over USB-C, but none of the existing options on the market was quite what he wanted. He looked around and eventually discovered the STUSB4500, a a USB power delivery controller chip that can be configured over I2C.

With a bit of nonvolatile memory onboard, it can retain its settings so he didn’t have to include a microcontroller in his design: just program it once and it can be used stand-alone to negotiate the appropriate voltage and current requirements when its plugged in.

The board that [Mansour] came up with is a handy way of powering your projects via USB-C without having to reinvent the wheel. Using the PC configuration tool and an Arduino to talk to the STUSB4500 over I2C, the board can be configured to deliver from 5 to 20 VDC to whatever device you connect to it. The chip is even capable of storing three seperate Power Delivery Output (PDO) configurations at once, so you can give it multiple voltage and current ranges to try and negotiate for.

In the past we’ve seen a somewhat similar project that used USB-PD to charge lithium polymer batteries. It certainly isn’t happening overnight, but it looks like we’re finally starting to see some real movement towards making USB-C the standard.