Adafruit PowerBoost 500 + Charger
Created by lady ada
https://learn.adafruit.com/adafruit-powerboost-500-plus-charger
Last updated on 2021-11-15 06:14:19 PM EST
©Adafruit Industries
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Table of Contents
Overview
3
Pinouts
5
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•
•
•
6
7
7
7
Power Pins
Control Pins
LEDs
Battery and USB connection
On/Off Switch
Downloads
• Datasheets & Files
• Schematic
• Fabrication Print
F.A.Q.
©Adafruit Industries
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13
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Overview
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 (https://adafru.it/duP), 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.
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The PowerBoost 500C has at the heart a TPS61090 boost converter from TI (https://
adafru.it/duQ). 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)
(https://adafru.it/dzw)
adafruit_products_1944iso_USB_ORIG.jpg (https://adafru.it/iQf)
To make this even more useful, we stuck a MicroLipo charger on the other side. The
charger circuitry is powered from a microUSB jack, and will recharge any 3.7V/4.2V
LiIon or LiPoly battery at 500mA max rate. There's two LEDs for monitoring the charge
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rate, a yellow one tells you its working, a green one lights up when its done. You can
charge and boost at the same time no problem, without any interruption on the output
so its fine for use as a "UPS" (un-interruptable power supply). Just be aware that the
charge rate is 500mA max, so if you're drawing more than ~300mA continuously from
the 5V output side, the battery will slowly drain since the charge rate is less than the
dis-charge rate.
adafruit_products_1944quarter_ORIG_298.jpg (https://adafru.it/iQA)
Great for powering your robot, Arduino project, single-board-computer such as
Raspberry Pi or BeagleBone! Each order comes with one fully assembled and tested
PCB and a loose USB A jack. If you are powering your project from USB, solder the
USB A jack in (a 3-minute soldering task). If you would like to use a terminal block,
pick up a 3.5mm 2pin block here (https://adafru.it/duR) and solder to the output spot
where the USB jack would go. Or dont solder anything in for a more compact power
pack.
If you're trying to figure out how much current your project is using, check out the CH
ARGER DOCTOR! (http://adafru.it/1852)
Pinouts
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!
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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 fullycharged. 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
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Using a bench-top supply or long wires can add too much inductance to the
input of the boost converter and destroy it! We really do recommend using Lipoly
batteries with short wires
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.
The LBO output is pulled up to Vin, and is not suitable for direct connection to
3.3V logic GPIO!
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. Wa
tch the polarity of the cable! the + and - markings next to the JST will let you know
which way is which.
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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)
Some third-party LiPo cells have JST connectors wired opposite from the
standard. Connecting these to the PowerBoost will damage your PowerBoost.
Double check the polarity before connecting.
On/Off Switch
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. (https://adafru.it/drN)
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
This tutorial assumes you are using a "break-before-make" switch. If you are not
sure that your switch is "break-before-make" solder in ONLY the EN and GND pin,
skipping the VBAT pin!
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The switch will go into the breakout
header, and attach to VBAT EN and GND
The switch is symmetric so as long as
those three pins are attached to the
switch you are good to go
For mechanical strength, we soldered in
all three pins. However, this only works
for "break-before-make" type swtches! If
you are not sure that your switch is
"break-before-make" or if your switch has
only two pins, solder in ONLY the EN and
GND pin, skipping the VBAT pin!
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Clip either one of the outside pins with
diagonal cutters
Use kapton tape to keep it in place while
you solder
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Before soldering, check that you have
the right three pins!
Solder in all three pins with any kind of
solder making sure you have a good
connection
Yay! Check your work...
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Clip off the long pins with diagonal
cutters
When the switch is to the left, the 5V
power will be on, you can tell because
the blue LED is lit
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Slide to the right to turn it off.
Downloads
Datasheets & Files
• TPS61090 datasheet (https://adafru.it/duS)(the DC/DC boost control chip used)
• MCP73831 datasheet (https://adafru.it/dvn) (the Lipoly charger chip used)
• EagleCAD PCB files on GitHub (https://adafru.it/pTb)
• Fritzing object in Adafruit Fritzing library (https://adafru.it/aP3)
Schematic
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Fabrication Print
Dimensions in Inches
F.A.Q.
Can I use the PowerBoost without a battery attached?
No. Please note that this board is designed to be used only with a LiPoly attached,
it won't work without a battery.
Without the battery installed, both CHG and DONE LEDs
are lit!
This is normal, the charger chip dimly lights both LEDs if it cannot detect a battery,
this lets you know that it is waiting for a battery to be plugged in!
We don't recommend running the PB500C without a battery, its not going to work
very well since there's no 'power path' from USB in to USB!
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