VFLEX Datasheet

Micro-USB gear never negotiates anything — it takes whatever 5V arrives at the plug, and lives or dies by how much of it survives the cable. VFLEX lets you set that voltage instead of hoping.

The Raspberry Pi that keeps flashing the undervoltage warning

This is the classic Micro-USB failure, and it hits the Pi 3, 3B+, Zero and Zero 2 W hardest.

The official Raspberry Pi supply isn't 5V — it's 5.1V. That extra 100mV isn't a rounding error, it's headroom for the drop across the cable, the connector and the board under load. The Pi's low-voltage detector trips below 4.63V, and Micro-USB is the worst offender for getting you there: small contacts, thin conductors, and phone-charger cables built for convenience rather than current. A 5.00V charger at the wall can easily arrive under 4.63V at the SoC the moment the CPU ramps or a USB device spins up. That's the lightning bolt, the throttling, and the random reboots.

With VFLEX you set 5.1V to match the official supply — or trim a little higher if a long cable or a hungry HAT is still pulling you down.

And everything else still on Micro-USB

Single-board computers, USB hubs, trail cameras, retro handhelds, test gear, older IoT boxes. All of it runs from a modern USB-C PD charger or power bank, at a voltage you choose.

What's Included

• VFLEX Base: Programmed to a 5–6V range. It cannot be set outside that window, so the cable can't be dialed up to a voltage that would damage a Micro-USB device.
• Micro-USB Adapter Cable: Terminates in a standard Micro-USB Type-B plug for a plug-and-play fit into the device's power input.

Why 5–6V

Micro-USB is a 5V connector, and a plug carrying much more than that will damage the device — so this bundle's base is locked to the safe window rather than left open across the full VFLEX range. The room above 5V is the whole point: it's what lets you match the Pi's 5.1V, or claw back the drop on a long run. Move in small steps and stop as soon as the device is stable.

Requirements

• USB-C Power Delivery (PD) capable wall adapter or power bank
• A device that takes 5V through a Micro-USB power input

Note: This cable delivers a fixed voltage and does not negotiate fast charging. Phones and tablets that expect to request a higher voltage will charge slowly or not at all — use their own charger for those.