0-1A Single-Supply, Low-Side, Current Sensor with Output 0 to 4.9V

  • Rajkumar Sharma
  • 34 Views
  • easy
  • Tested
  • SKU: EL143414
  • Quote Now

This single-supply, low-side, current sensing solution accurately detects load current between 0 and 1A. The current sensor measures 0 to 1A across the shunt resistor, providing 0 to 4.9V output. The OPA320 features wide bandwidth and low offset voltage making it an excellent amplifier for this design. With a single 5V supply, the LM7705 negative bias generator extends the linear output range of the amplifier below 0V. This enables the op-amp to produce a linear output for a zero-input current condition. The wide sensing range of the design allows for precise measurement of small load currents (i.e., low-power or shutdown modes) and higher currents up to 1A. The LM7705 functions as an inverting charge pump and regulates its output to -0.23V when powered by a single supply. By biasing the negative supply (VS-) of the op-amp to -0.23V, the linear output range of the device is extended below 0V. A linear output at 0V allows a calibrated measurement of zero-input current.

Features

  • Power Supply 5V DC @ 10mA
  • Load Current 0 to 1Amp
  • Output 0 to 4.9V
  • Full-Scale Error +/-0.1%
  • PCB Dimensions 28.58 x 14.13 mm

Connections

  • CN1: Pin 1 = VCC 5V DC, Pin 2,3 = GND, Pin 4 = Output
  • CN2: Load Pin 1,2 = Load, Pin 3,4 = GND
  • D1 Power LED

Schematic

Parts List

NOQNTYREFDESC.MANUFACTURERSUPPLIER SUPPLIER PART NO
12CN1,CN24 PIN MALE HEADER PITCH 2.54MMWURTHDIGIKEY732-5317-ND
24C1,C4,C5,C7100nF/50V CERAMIC SMD SIZE 0805YAGEO/MURATADIGIKEY
33C2,C3,C622uF/10V CERAMIC SMD SIZE 0805YAGEO/MURATADIGIKEY
42C8,C910uF/10-16V TANTLUM SIZE 1210KEMET/MUARATADIGIKEY
51D1LED RED SMD SIZE 0805LITE ON INCDIGIKEY160-1427-1-ND
61R11K 5% SMD SIZE 0805YAGEO/MURATADIGIKEY
71R20.1E/2W 1% SMD SIZE 0805BOURNSDIGIKEYCRA2512-FZ-R100ELFCT-ND
81R37.5K 1% SMD SIZE 0805YAGEO/MURATADIGIKEY
91R4360K 1% SMD SIZE 0805YAGEO/MURATADIGIKEY
101U1OPA320AQDBVRQ1TIDIGIKEY296-45320-1-ND
111U2LM7705 VSOP8TIDIGIKEYLM7705MM/NOPBCT-ND

Connections

Input-Output Diagram

Gerber View

Photos

Video

LM7705 Datasheet

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