Power Connectors Interconnection

A project log for CLN17: $15 BoM Closed-Loop Driver for NEMA17

A compact, silent, high-performance open-source closed-loop (servo) stepper motor driver that supports CAN-FD and USB-C with PowerDelivery

anton-khrustalevAnton Khrustalev 09/26/2023 at 13:480 Comments

The USB Type-C and power connectors (both XH2.5) are connected in parallel. Each XH2.5 connector is equipped only with a protective resettable fuse rated at 2A, while the USB Type-C has only a protective diode. Therefore,

Simultaneous use of several power sources
To avoid damaging the power supply, do not connect two different voltage sources to the XH2.5 connectors or apply power to the USB Type-C and XH2.5 connectors simultaneously, if the USB voltage is higher than the XH2.5 connector's voltage (VXH < VUSB).
The maximum current rating of a fuse
The maximum current rating of a self-resetting fuse decreases with rising ambient temperature. For example, at 25°C, the fuse can carry up to 2A, but at 85°C, the maximum current drops to 0.8A.

This power architecture allows flexible and efficient power distribution across a device network. For example, with 7.5W motors (like Nema17 34mm body length), you can power the driver through a USB Type-C 20V 3A connection, and the POWER connector can supply five similar motor assemblies.

Network driver connection
When connecting additional drivers, it is crucial to ensure that the total current passing through the connector at any given moment does not exceed 2A. This limitation allows for a greater number of drivers to be connected, as long as they are not all operated simultaneously.
For powering the network of drivers, it is highly recommended to use a star topology instead of a linear one. Excessive transitions through the drivers should be avoided as they can result in unnecessary heat losses.