www.AttoPilotInternational.com
Photo Tips for Soldering
AttoPilot International LLC, 2011
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Features
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New! Three Ideals ranges for small robotics applications:
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New 50 V / 180 Amps
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50 V / 90 Amps
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New 13.6 V / 45 Amps
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Low zero current offset and high sensitivity
• Analog output scaled for 3.3V ADC
• Self powered
• Compact thin design (4 x 15 x 19mm)
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Analog Voltage Outputs for Sensed Parameters:
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50V/180A = 63.69mV / Volt 18.30mV / Amp
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50V/90A = 63.69mV / Volt 36.60mV / Amp
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13.6V/45A = 242.3mV / Volt 73.20mV / Amp
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New! Re-designed to accept direct solder connection with
Deans Ultra connectors
Description
A small voltage and current sense
PCB. DC current is determined by
measuring voltage drop across a
shunt resistors then converted to
analog voltage output by the
Texas Instruments INA-169.
Voltage sense is accomplished by
scaling to 3.3V ADC range by a
precision resistor divider.
The current limit coincides with
maximum power rating of the
shunt resistors.
Compact DC Voltage and Current Sense PCB with Analog Output
Assembly
The PCB is supplied without leads or connectors. Care must be exercised in soldering,
though the pad sizes are large enough to accommodate 12 gauge heavy duty leads (see
photograph below). Smaller gauge leads may be easier to solder without creating shorts.
The sensed current path is from “In+” to “Out+”. It is important to completely flood this
connection path through shunt resistors with solder, on both sides of the PCB. As-supplied,
the PCB has some solder flooding in this area, but it is up to you to ensure this is maintained
after attachment of leads. The shunt resistors each have four terminals in a Kelvin
configuration. Two terminals carry the shunt current load, and the other two terminals are
used for the voltage drop monitor INA-169.
It is important that both shunt resistors carry equal current load for sensor accuracy. To
ensure equal current load, the solder pads have a large via holes through which the leads
must pass through then be flooded with solder. Pass the “In+” and “Out+” leads through the
large via holes and solder flooded on top and bottom of the PCB. The “GND” pads also have
a large via hole however large current does not flow through the PCB from the GND leads;
the PCB “GND” pad is merely a small current common GND connection. The large current
flow in GND is from one lead to the other through the pad and solder-flooded via hole itself.
