Parallax PowerPal User manual

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PowerPal Selectable Voltage 3-Amp Breadboard
Power Supply (#32133)
The PowerPal is a breadboard-friendly 3A power supply module that allows you to select from
four different output voltage levels. It’s ideal for regulang power to the Propeller FLiP Try-it Kit
or other breadboard based projects along with a baery pack or wall-mount supply. It comes
with two sturdy 2x2 headers which plug directly into the breadboard rail. Through-hole pads are
provided that allow the user to oponally add an addional VOUT header or on-off switch
leads.
Features
●Rotary switch for user-selectable voltage output choices: 3.3 V, 5 V, 6 V, 7.5 V
●3 Amp connuous load switching power supply
●4 Amp peak surge rang is ideal for servo motors
●Barrel Jack or 0.1 inch pitch headers for 5-16 VIN
●Through-hole pads for oponal On/Off switch leads
●Green power-status LED
●Over-current and over-voltage protecon
●Over-temperature and short-circuit protecon
●0.1 inch (2.6 mm) diameter mounng hole
●All headers on a 0.1 inch (2.54 mm) grid
Copyright © Parallax Inc.
PowerPal Module ((#32133)
v1.0 11/20/2018 Page 1 of 6

Key Specifications
●Voltage input requirements: +5 to +16 VDC
●Voltage output selectable by user: 3.3V, 5V, 6V, or 7.5V
●Voltage output tolerance: Typically 2% at a 2A load, 3% at a 4A peak load
●Current rang: constant load 3 A; absolute peak 4 A
●Nominal switching frequency: 770 KHz
●Efficiency: up to 95%
●Operang temperature: -13 to +185 °F (-25 to +85 °C)
●Dimensions: PCB 1.5 x 1 inch (39 x 24 mm); 0.1 inch (2.6 mm) mounng hole
Feature Descriptions
Read the full explanaon of each labeled feature on the pages that follow this diagram.
Copyright © Parallax Inc.
PowerPal Module (#32133)
V1.0 11/20/2018 Page 2 of 6

1) Rotary Voltage Output Selector
Select an output voltage (VOUT) using a small screwdriver to rotate the arrow. The markings on
the rotary selector and the voltage are shown on the back of the PowerPal:
0 = 3.3V, 1 = 5V, 2 = 6V, 3 = 7.5V
While rotang the voltage selector between opons, the output voltage will be limited to about
1.8V and the VOUT LED will switch off to signal that the voltage selecon is not valid.
Take care when changing voltages! If your project expects 3.3V, but you select
7.5V even briefly, it may cause significant damage!
Always unplug the external power supply while changing voltage. We strongly suggest
unplugging the PowerPal from the breadboard and testing the VOUT setting with a
multimeter before connecting the PowerPal to your project, especially if you have any doubts
about the module or your power supply.
2) VIN Access Header
The VIN Header is a 0.1” pitch 3-pin header. To provide some polarity protecon for the user,
the two outer pins are negave, and the center pin is posive.
The 3-pin VIN header is connected directly to the DC Jack, and so care should be taken not to
supply power into the PowerPal through both the DC Jack and the 3-pin VIN header at the same
me.
Located between the DC Jack and 3-pin VIN header are two addional unpopulated + VIN
through-hole pads. These do not have any headers installed, and are intended for advanced
users who might want to install alternave connectors here. If you not need these, then please
ignore them!
3) VOUT ON LED
The green VOUT ON LED will light up when the rotary voltage output selector is set to one of
the four posions, and VOUT is acve. The brightness will vary depending on the output voltage
selected.
If the PowerPal detects an over-current condion, the VOUT ON LED will start blinking rapidly to
indicate a fault. If this occurs, disconnect power immediately and invesgate.
If the VOUT ON/OFF pads are shorted together, the VOUT ON LED will go off, as the output is
disabled.
Copyright © Parallax Inc.
PowerPal Module (#32133)
V1.0 11/20/2018 Page 3 of 6

4) VOUT Breadboard Headers
The PowerPal has two blocks of 4-pin headers posioned to allow inseron directly into the
breadboard power rail. The top pins are all posive voltage, and the boom row of pins (nearest
the board edge) are negave GND. The GND pins are idenfied by a white square around the
pads, both on the top and the boom of the pcb.
CAUTION! Before connecting power to the PowerPal, ensure that it is oriented
in the breadboard, such that the positive and negative outputs match the
circuit. Use color-coded wires and, if available, breadboard markings, to
differentiate VOUT and GND.
5) VOUT Access Header Pads
Located between the breadboard headers are a set of 3-pin through-hole pads that allow users
to fit a custom VOUT connector. The pads are spaced at a 0.1” pitch.
The center pin is posive, and the two outer pins negave/GND. The GND pins are idenfied on
both sides of the PCB by the white silk square around the pad.
6) VIN DC Jack
The DC Jack accepts a 2.1mm center-posive barrel plug. It is compable with many different
power source opons, including wall-mount power supplies and baery packs sold by Parallax
Inc.
The jack socket is connected directly to the VIN Header pins, located behind the DC Jack. The
dual connecon opon allows you to supply power through one, and source power from the
other. This might be useful to power high-voltage servo motors at baery supply voltage, while
PowerPal VOUT could be set to provide a lower voltage to your microcontroller and the rest of
your project’s circuits.
If your project required two PowerPals, you can power them both from one DC-Jack by linking
the VIN headers together with a short 3-pin jumper cable (751-00010).
WARNING! DO NOT connect a power input source to both the DC Jack and VIN
headers at the same time!
Copyright © Parallax Inc.
PowerPal Module (#32133)
V1.0 11/20/2018 Page 4 of 6

7) Switching Power Supply
The center area of the PowerPal pcb contains the switching power supply IC and supporng
components.
CAUTION! Components will become HOT when supplying high current loads!
TIP! The PCB is designed to act as heatsink, and the reverse of the PCB features
a continuous 2 oz copper ground plane which will become warm in normal use.
The PowerPal uses a switching buck regulator to efficiently drop VIN to the user selected VOUT
voltage.
It is not possible to output voltage larger than the input voltage, and the available output
current will depend on the input current. The output voltage will start to drop once you exceed
the power (voltage or current) available from your input power supply.
To minimise output voltage drop when powering high current (>2A) loads, ensure that VIN is at
least 1.5V more than your required VOUT.
8) Mounting Hole
The mounng hole is 0.1 inch (2.6mm) diameter, with clearance around up to 0.2 inches
(5.4mm), suitable for M2.5 or #3 mounng hardware .
The hole has no electrical connecon, but care should be taken when using metal fixings, and a
Nylon washer is recommended.
The locaon of the hole makes it convenient to fix a 12mm (15/32”) long nylon spacer, which
would act as a leg to support the PowerPal when inserted into a breadboard. Example: Digi-Key
part numbers: 1772-2059-ND (12mm Nylon spacer) and 36-29331-ND (6mm Nylon screw)
9) VOUT On/Off Pads
These oponal through-hole pads allow remote control of the VOUT state. When the on/off pins
are shorted together, VOUT will be switched off. The pads accept a 0.1” pitch 2-pin header.
VOUT ON/OFF could be controlled by a simple switch, or electronically by driving the ON/OFF
signal pin low using a microcontroller. The ground pin is surrounded by a white silkscreen
marking, and the signal pin is not.
Copyright © Parallax Inc.
PowerPal Module (#32133)
V1.0 11/20/2018 Page 5 of 6

PCB Dimensions
Revision History
Version 1.0: original release.
Copyright © Parallax Inc.
PowerPal Module (#32133)
V1.0 11/20/2018 Page 6 of 6