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10μA-10mA Low-Side Current Sensor
- Rajkumar Sharma
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- easy
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- 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
| NO | QNTY. | REF. | DESC. | MANUFACTURER | SUPPLIER | SUPPLIER PART NO |
|---|---|---|---|---|---|---|
| 1 | 1 | CN1 | 4 PIN MALE HEADER PITCH 2.54MM | WURTH | DIGIKEY | 732-5317-ND |
| 2 | 1 | CN2 | 2 PIN SCREW TERMINAL PITCH 5.08MM | PHOENIX | DIGIKEY | 277-1247-ND |
| 3 | 1 | C1 | 1uF/25V CERAMIC SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 4 | 1 | C2 | 194PF/25V CERAMIC SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 5 | 1 | C3 | 10PF/50V CERAMIC SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 6 | 1 | C4 | 100nF/50V CERAMIC SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 7 | 1 | C5 | 10uF/25V CERAMCIS SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 8 | 1 | D1 | LED SMD SIZE 0805 | OSRAM | DIGIKEY | 475-1278-1-ND |
| 9 | 1 | J1 | 2 PIN MALE HEADER PITCH 2.54MM | WURTH | DIGIKEY | 732-5315-ND |
| 10 | 1 | R1 | 50K 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 11 | 1 | R2 | 25E 0.1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 12 | 1 | R3 | 100E 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 13 | 1 | R4 | 100K 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 14 | 1 | R5 | 1K 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 15 | 1 | R6 | 511K 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 16 | 1 | R7 | 10M 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 17 | 1 | U1 | INA326 | TI | DIGIKEY | INA326EA/2K5CT-ND |
| 18 | 1 | J1 | SHUNT FOR JUMPER | SULINS CONNECT | DIGIKEY | S9001-ND |
Connections
Gerber View
Photos
Video
INA326 Datasheet
PCB
