Comparison of power supply & management hardware

Comparisons of hardware used for either powering or managing the power for embedded systems.

Comparison of power supply/management hardware
This comparison is designed with the goal of making it easier to sift through all the power supply solutions for embedded systems with an emphasis on UPS functionality. They are devices usually to be used in conjunction with basic PSUs. It could contain both commercially available products or just schematics of designs (ideally which have been tested).

Explanation of columns:
 * Input: list of input power sources (PSU, battery, etc) ordered by their priority. Voltage range, interface (USB, header pins, etc), (max required current).
 * Output: list of outputs voltages, maximum currents, and interface.
 * Target system: the system it was tailored to. List what makes it specific.
 * 'backpack' (aka 'shields', 'capes', 'hats', 'cloaks', 'armour' etc) denotes it was designed to physically piggyback onto that specific piece of hardware through header pins, fastener holes, etc.
 * 'software' denotes there is software to control the unit but which has been written specifically for that system. In theory it could be re-written for other platforms (if its open source).
 * UPS:
 * yes (green): it is a fully fledged standalone UPS, requires no additional hardware other than a PSU. Plug it in and it works.
 * yes (yellow): if it was designed specifically as a key component to making a UPS (eg power management regulator/controller/multiplexer/switch) but may require other pieces of off-the-shelf hardware (eg battery, battery charger, super capacitors, nuclear generator, etc.). Should list what is required.
 * Battery Charger: has a battery charger onboard. Should list battery chemistries supported, including supercapacitors.
 * DC-DC converter: Types of onboard voltage converters used for main power conversions including battery charging. Linear regulators can be quite inefficient compared to switched regulators. Doesn't include low power ones used for MCUs, etc.
 * Interface: The interface with the embedded system, if any (I2C, 1-wire, SPI, serial, etc). Simple interrupts don't count.
 * Interrupts: List of interrupts it can signal events with (eg low battery). Usually are just pins which go high/low signalling something has changed. They cannot require polling by the embedded system to work (eg can't have interrupts with I2C without using a 5th wire or the hardware playing master).
 * Efficiency: Useful information which should be supplied by manufacturer for matching a supply with the load requirements to achieve good performance (eg maximize battery life).
 * Docs: Documentation/datasheet available. Ideally should be a concise portable published document such as a PDF.
 * yes (green): acceptable documentation, at least basic block schematics, and API published (if applicable). If open source, it should include PCB layout.
 * partial (yellow): some documentation but missing some key components.
 * Open Source: If so, list licence (eg GPL) and link to where source can be found if different from main link.

Comparison of PSUs
TODO: compare basic power supplies, commercial or otherwise, from mains power eg wall warts.
 * name/brand/identification/markings
 * input specs
 * output specs
 * efficiency: how they actually perform % efficiency over their rated output. Maybe just state the peak % at V, A.
 * performance: how they actually perform in terms of input and output power (eg with output voltage dropping no less than -5% for 5V supply as per USB specs)
 * quality: does it work alright for things such as RPi or should it be avoided (some wall warts from ebay).