July 2025 – Beyondlogic

Adding a TCPC to Zephyr for USB Power Delivery

July 28, 2025 Craig Peacock 1

The Zephyr RTOS has support for USB-C Power Delivery through the software port of the Google ChromeOS Type-C Port Manager. USB Power Delivery is a protocol used on USB Type-C connectors to negotiate power at different voltage levels – typically 5V, 9V, 12V, 15V, 20V, but can be as high as 48V/240W with the new PD revision 3.1. As USB-C becomes the universal standard for low power chargers, it allows different devices such as phones, laptops, LCD screens, mini PCs, lights, label printers, bike lights etc to use a common charger, reducing e-waste and end-user confusion of what plug pack …

Review: Gatetop Low Voltage 12 – 48V DC/AC E27 Light Bulb

July 21, 2025 Craig Peacock 0

A couple of weeks ago, we reviewed the Heetech Low Voltage 12 – 85V DC/AC E27 Light Bulb. While it had a large input range of 12 to 85V, the luminous output started to dim as the voltage fell below 13.0V. If operated on a 12V battery, the reduction in light intensity was noticeable as the battery’s terminal voltage reduced throughout the night. It was also advertised and marked as 9W, but only consumed 7 to 8 watts. At that stage, it was time to try a different product and see if we could find anything better. I ordered two …

Review: USB-PD 65W Fast Charging Module (XPM52C)

July 10, 2025 Craig Peacock 3

This USB-PD (Power Delivery) Charging module is based on the XPM52C 65W USB-PD Multi-protocol Buck Converter. It allows USB devices (mobile phones, tablets, laptop computers, cameras etc) to be efficiently charged from a low voltage DC power source (8 to 30V DC) such as 12V/24V battery or power station. While my interest was in the USB-C power delivery capability, the device supports a range of legacy fast-charging protocols: This module is available from your usual cheap electronics sources such as AliExpress, Amazon, and Banggood. As the vendors normally don’t list the main part in their descriptions, search for “PD 65W …

Review: Heetech Low Voltage 12 – 85V DC/AC E27 Light Bulb

July 7, 2025 Craig Peacock 0

In off-grid systems, it can make sense to use a low voltage DC light bulb, instead of having the overheads of a DC to AC inverter – in terms of capital cost, quiescent (idle) current, conversion efficiency and risk of electrocution. For example, in a shed or other de-attached structure you could have a small 12V or 24V PV Solar system and run your lighting directly from that source. LED bulbs exist in standard E27 (Edison screw, 27mm) and B22 (Bayonet cap, 22mm) that can be powered from lower voltages – typically 12V, 24V or 48V. We review one such …