PowerBoost 500C is the perfect power supply for your portable project! With a built-in battery charger circuit, you'll be able to keep your project running even while recharging the battery! This little DC/DC boost converter module can be powered by any 3.7V LiIon/LiPoly battery, and convert the battery output to 5.2V DC for running your 5V projects.

Like our popular 5V 1A USB wall adapter, we tweaked the output to be 5.2V instead of a straight-up 5.0V so that there's a little bit of 'headroom' for long cables, high draw, the addition of a diode on the output if you wish, etc. The 5.2V is safe for all 5V-powered electronics like Arduino, Raspberry Pi, or Beagle Bone while preventing icky brown-outs during high current draw because of USB cable resistance.

The PowerBoost 500C has at the heart a TPS61090 boost converter from TI. This boost converter chip has some really nice extras such as low battery detection, 2A internal switch, synchronous conversion, excellent efficiency, and 700KHz high-frequency operation. Check out these specs!

• Synchronous operation means you can disconnect the output completely by connecting the ENable pin to ground. This will completely turn off the output
• 2A internal switch (~2.5A peak limiting) means you can get 500mA+ from a 3.7V LiPoly/LiIon battery. We had no problem drawing 1000mA, just make sure your battery can handle it!
• Low battery indicator LED lights up red when the voltage dips below 3.2V, optimized for LiPo/LiIon battery usage
• Onboard 500mA charge-rate 'iOS' data resistors. Solder in the USB connector and you can plug in any iPhone or iPod for 500mA charge rate. Not suggested for large iPads.
• Full breakout for battery in, control pins and power out
• 90%+ operating efficiency in most cases (see datasheet for efficiency graphs), and low quiescent current: 5mA when enabled and power LED is on, 20uA when disabled (power and low batt LED are off)

If you're trying to figure out how much current your project is using, check out the CHARGER DOCTOR!

For many people, the PowerBoost 500C can be used with just the microUSB charge input, battery plug and power outputs. However, we have a couple handy breakouts so lets get started!

Power Pins

There's three power voltages, the USB input for charging the battery (4.75-5.25V whatever is coming out of the USB port), the battery itself (3-4.2V) and the output (5-5.2V)

• USB - this is the micro USB 5V power pin. It's the pin that is used to charge the battery, NOT the output power! You can use this if you want to grab power from the microUSB port when it is plugged in
• GND - this is the power ground. This boost converter is not 'isolated' - the ground input is the same as the ground output
• BAT - this is the battery input, connected directly to the JST connector. For most Lithium batteries, this will range from 3.0V when near-dead to 4.2V when fully-charged. Higher voltages will let you draw more current and in general, are more efficient. Try to keep the wires going to this pin nice and short - 3" or less is best!
  
• 5V - this is the boosted output. When the board is running, the voltage will be 5.2V approximately. It may dip down to 5V as the current draw starts to go up (over 500mA). When the board is disabled, this output is 'floating' but you should still try not to apply a voltage to it while the board is disabled. There's a green LED connected to this pin which will let you know when there's power output

Control Pins

There's two 'control' pins.

• EN - this is the 'enable' pin. By default it is pulled 'high' to VBAT. To turn off the booster, connect this pin to ground. The switch can be as small as you like, it is just a signal. Contrast this to an inline power switch which would have to be able to handle up to 2A of current! When the chip is disabled the output is completely disconnected from the input.
• LBO - not a leveraged buy out! this is the Low Battery Output. By default it is pulled high to BAT but when the charger detects a low voltage (under 3.2V) the pin will drop down to 0V. You can use this to signal when its time to shut down or alert the user that the battery is low. There is also a red LED connected to this pin.

LEDs

There are four onboard LEDs.

• The Blue LED sits next to the USB connector socket, and indicates the 5V output power state.
  
• The Red LED is next to the battery JST port and indicates when the battery voltage is below 3.2VDC (Low Battery Output)
• The Yellow LED is next to the microUSB connector and indicates when the battery is being charged
• The Green LED is also next to the microUSB connector and indicates when the battery is done charging (all full)
  

Battery and USB connection

You can connect a battery to the breakout strip or to the JST connector. All of Adafruit batteries come with JST cables that will plug in nicely so we strongly suggest that. Watch the polarity of the cable! the + and - markings next to the JST will let you know which way is which.

The USB connector can be soldered on to create a portable 'USB power pack'. The two data lines on USB have resistor dividers that match Apple charger values so that you can plug any iOS device in to charge. 99% of other phones, devices and tables are totally cool with these resistors as well. You can always short the D+ and D- lines if you happen to have a phone that wants shorted data lines.

If you don't want a USB connector attached, there are two holes that are designed for a 3.5mm spaced terminal block (not included)

The PowerBoost 500C does not come with an on/off switch for the output, but its very easy to add one! Just grab a Breadboard friendly SPDT slide switch from the adafruit shop.

We will be turning the boost on/off via the ENABLE pin, so the switch does not have to carry any power, it is only signalling to the boost converter what to do. This means the switch can be small. Use any switch you like, if it is 0.1" spacing thats ideal. If your switch only has two pins instead of three, tie one pin to GND and the other pin to EN - when the switch is closed, the power will turn off

Datasheets & Files

• TPS61090 datasheet (the DC/DC boost control chip used)
• MCP73831 datasheet (the Lipoly charger chip used)
• EagleCAD PCB files on GitHub
• Fritzing object in Adafruit Fritzing library

Schematic

Fabrication Print

Dimensions in Inches