Pololu Big Pushbutton Power Switch with Reverse Voltage Protection, MPPololu
The Pololu Pushbutton Power Switch is a compact, solid-state power switch that features built-in reverse-voltage protection and is controlled by a momentary pushbutton: one push turns on power and another push turns it off. This is a patented design initially created for use in our own products as an alternative to bulky mechanical switches. Because the switched current does not flow through the mechanical switch, a large variety of small, low-power switches can be used to control a substantial amount of power. The use of momentary switches also allows multiple switches to be used in parallel to control the power to one load.
The board has a small pushbutton already installed and offers convenient points for connecting external pushbutton or tactile switches in parallel. It also offers several alternate pushbutton connection options that result in push-on-only or push-off-only operation, and additional inputs enable further power control options like allowing the load to turn off its own power, which can be beneficial when used with battery chemistries sensitive to over-discharging.
Warning: Do not use this switch as an emergency cutoff or similar safety disconnect in applications where failure to cut power could lead to injury or property damage.
The switch and control inputs control the state of a latching circuit that in turn controls a pair of power MOSFETs through which the main current flows. Four versions of the Pololu Pushbutton Power Switches are available:
- Mini Pushbutton Power Switch LV
- Mini Pushbutton Power Switch SV
- Big Pushbutton Power Switch MP
- Big Pushbutton Power Switch HP
The two Mini Pushbutton Power Switches are smaller, lower-current versions that are useful for applications with tight size constraints or lower power requirements. Also, the the Mini LV is the only one of the four that works below 4.5 V; since it can operate down to 2.2 V, this version can be used with a single lithium cell battery.
The pinout of the Big version is the same as the pinout of the Mini version with several additional redundant connection points for convenience, including main power connections that are compatible with 5 mm terminal blocks.