Power your Teensy from a common 9 V battery!

What is it?

This is Monolithic Power's MPM3620A Buck Converter as the heart of a small (17.93 x 7.75 mm) power management add-on board that mounts above the USB connector of the Teensy 3.X microcontroller.

From the data sheet: "The MPM3620A is a synchronous, rectified, step-down module converter with an integrated inductor, two capacitors, and power MOSFETs. It offers a compact solution that requires only 5 external components to achieve a 2 A continuous output current with excellent load and line regulation over a wide input-supply range. Also, it provides fast load transient response."

The idea is that a high voltage source from 8 to 12 V can supply your Teensy-based project with the buck converter supplying 5 V at up to 2 A to provide input voltage for the Teensy as well as to power any peripheral 5 V circuitry like strings of leds. There is an additional 3V3, 300 mA low-drop out regulator on the board to supply 3V3 to other circuits with more current than can be supplied (<100 mA) by the on-board Teensy regulator.

The board has a slide switch to turn the 5 V and 3V3 power on or off, allowing you to turn the Teensy on or off too. The red led indicates fault conditions and won't light under normal operating conditions.

The result is a small, convenient power management board that mounts directly on the Teensy expanding the range of voltage and current available to meet most project needs.

Why did you make it?

I usually use LiPo batteries and have designed two (here and here) LiPo battery chargers currently available for sale on Tindie. They work great with the Teensy and are usually sufficient for most projects. However, there are several robotic applications where the main power source is a 12 volt battery, needed to drive power-hungry servos and motors. In these cases, it is convenient to run all the circuitry from a single battery source. Also, I like the idea of using common 9 V batteries to power some portable Teensy projects. It is in many cases easier to replace a 9 V battery than it is to recharge a LiPo.

This board allows the Teensy to be powered from higher voltage sources that would instantly fry it if connected directly to the Teensy VIN (< 5.5V!). The board provides a high-current (2 A) source of 5 V as well as a low-current (300 mA) source of 3V3 volts that should meet most portable, wearable needs and those for robotics and UAVs too.

What makes it special?

This is a small, convenient add-on board made possible by the latest in integrated power technology from Monolithic Power. With its embedded FETs, inductor and capacitors, the 3 x 5 mm MPM3620A makes sophisticated power management available in a very small form factor.

Order the board from OSH Park and assemble your own, or order the fully assembled and tested board from me and see how useful multiple voltage spigots mounted on your Teensy can be!