SEN-10643 SparkFun

www.AttoPilotInternational.com Compact DC Voltage and Current Sense PCB with Analog Output Features Description New Three Ideals ranges for small robotics applications: A small voltage and current sense o New 50 V / 180 Amps PCB. DC current is determined by 1 o 50 V / 90 Amps measuring voltage drop across a o New 13.6 V / 45 Amps shunt resistors then converted to Low zero current offset and high sensitivity analog voltage output by the Analog output scaled for 3.3V ADC Texas Instruments INA-169. Self powered Voltage sense is accomplished by Compact thin design (4 x 15 x 19mm) scaling to 3.3V ADC range by a Analog Voltage Outputs for Sensed Parameters: o 50V/180A = 63.69mV / Volt 18.30mV / Amp precision resistor divider. o 50V/90A = 63.69mV / Volt 36.60mV / Amp o 13.6V/45A = 242.3mV / Volt 73.20mV / Amp The current limit coincides with New Re-designed to accept direct solder connection with maximum power rating of the Deans Ultra connectors shunt resistors. 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. Photo Tips for Soldering AttoPilot International LLC, 2011 1180 Amp Sensor Recommended Lead Arrangement For the 180 Amp sensor, it is recommended to use doubled pairs of 12 gauge wire, as shown above. AttoPilot International LLC, 2011 2 Figure 1 Schematic