Advertisement
Circuit Description and Operation
CAUTION: The PCB near the cell holders may get hot! However, when the Li-ion Power
Pack is properly installed in the under-belly of the robot, any potentially hot areas on the
PCB are safely protected.
With cells installed in their respective holders, and with no external connections to the input/output jacks,
the circuitry is inactive and there is no current flow (other than some very, very small leakage current
through the inactive charging circuits).
Upon application of +5 to +12 VDC to the Charging Power Input jack (J1), the following happens:
a) The Charging Power Input (Green LED) is activated.
b) Each cell is electrically disconnected and isolated from the other.
c) The Cell Power Output jacks are disconnected from the cells, and disabled.
d) The dual charging circuits begin a qualification mode to determine each cell's characteristics.
e) After checking the cells, LED status indicators are activated. If required, each cell begins
charging their respective cells.
When Charging Power is removed, it results in the following:
a) Cell charging circuits are disabled and Status indicator LEDs are disabled.
b) The cells are electrically connected into a series configuration.
c) Cell Power Output jack is connected to the cells, resulting in a 7.4 VDC (max.) output.
Jack/Plug/Indicators Functional Descriptions
Charge Power Input: 2.1 mm barrel jack, center positive. +5 to +12 VDC input. Do not reverse the
input voltage. Charging time is dependent on the amperage available from the power supply you
choose, as well as the capacity of the cells you choose.
Cell Power Output: Polarized, right angle, female, bottom pin positive.
This Power Output jack is the output from the cells.
When there is no Charge Power Input (i.e. when the wall charger is disconnected from the PCB),
the two 3.7 volt cells are electrically connected together in a series configuration, and the
resulting power (3.7 VDC x 2 cells = 7.4 VDC) is available at this jack.
Upon application of Charge Power (such as from a wall transformer), Cell Power Output is
disconnected from the on-board cells, and this jack is disabled.
Green LED: Charge Power Indicator—whenever charging power is applied to the Charging Power Input
barrel jack, the board is receiving power.
Cell A Blue Status: This LED indicates the charging status of Cell A.
•
Solid = The cell is charging.
•
Blinking = The cell has been fully charged.
Copyright © Parallax Inc.
Web Site: www.parallax.com
Forums: forums.parallax.com
Sales: sales@parallax.com
Technical: support@parallax.com
Li-ion Small Robot Power Pack-Charger (#28988)
Office: (916) 624-8333
Fax: (916) 624-8003
Sales: (888) 512-1024
Tech Support: (888) 997-8267
v1.2 3/3/2015 Page 9 of 10
Advertisement
