10μA-10mA Low-Side Current Sensor

  • Rajkumar Sharma
  • 49 Views
  • easy
  • Tested
  • SKU: EL145610
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This single-supply, low-side, current-sensing solution accurately detects load current between 10μΑ and 10mA. A unique yet simple gain-switching network was implemented to measure the three-decade load current range accurately. The linear range of the output is from 100mV to 4.90V. INA326 instrumentation amplifier is used since low-side sensing is desirable because the common-mode voltage is near the ground. Therefore, the current sensing solution is independent of bus voltage, which allows for using single-supply, rail-to-rail input/output (RRIO) amplifiers. Low-side current sensing places a shunt resistor between the system load and the ground. The current drawn by the load generates a voltage across the shunt resistor. The output voltage of the circuit is equal to the current sense across the shunt resistor and the gain of the amplifier. A high-value resistor is used as a shunt for accurate current sense. It is advisable to use 0.1% tolerance shunt resistor R2.

Credits: Circuit is from Texas Instruments Application Note

Features

  • Supply 5V DC
  • Input Current Range 10uA to 10mA
  • Output 100mV(0,1V) to 4.90V
  • On Board Power LED
  • Very Small Board
  • PCB Dimensions 28.10 x 17.30 mm

Connections

  • CN1L Pin 1 = VCC 5V DC, Pin 2 = GND, Pin 3 = GND, Pin 4 = Output 100mV to 5V
  • CN2: Pin 1 = Current Input, Pin 2 = GND
  • D1: Power LED
  • J1: Gain Set

Schematic

Parts List

NOQNTY.REF.DESC.MANUFACTURERSUPPLIER SUPPLIER PART NO
11CN14 PIN MALE HEADER PITCH 2.54MMWURTHDIGIKEY732-5317-ND
21CN22 PIN SCREW TERMINAL PITCH 5.08MMPHOENIXDIGIKEY277-1247-ND
31C11uF/25V CERAMIC SMD SIZE 0805YAGEO/MURATADIGIKEY
41C2194PF/25V CERAMIC SMD SIZE 0805YAGEO/MURATADIGIKEY
51C310PF/50V CERAMIC SMD SIZE 0805YAGEO/MURATADIGIKEY
61C4100nF/50V CERAMIC SMD SIZE 0805YAGEO/MURATADIGIKEY
71C510uF/25V CERAMCIS SMD SIZE 0805YAGEO/MURATADIGIKEY
81D1LED SMD SIZE 0805OSRAMDIGIKEY475-1278-1-ND
91J12 PIN MALE HEADER PITCH 2.54MMWURTHDIGIKEY732-5315-ND
101R150K 1% SMD SIZE 0805YAGEO/MURATADIGIKEY
111R225E 0.1% SMD SIZE 0805YAGEO/MURATADIGIKEY
121R3100E 1% SMD SIZE 0805YAGEO/MURATADIGIKEY
131R4100K 1% SMD SIZE 0805YAGEO/MURATADIGIKEY
141R51K 1% SMD SIZE 0805YAGEO/MURATADIGIKEY
151R6511K 1% SMD SIZE 0805YAGEO/MURATADIGIKEY
161R710M 1% SMD SIZE 0805YAGEO/MURATADIGIKEY
171U1INA326TIDIGIKEYINA326EA/2K5CT-ND
181J1SHUNT FOR JUMPERSULINS CONNECTDIGIKEYS9001-ND

Connections

Gerber View

Photos

Video

INA326 Datasheet

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