SBOS601A February   2012  – December 2021 INA230

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Related Products
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements (I2C)
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Basic ADC Functions
      2. 8.3.2 Power Calculation
      3. 8.3.3 Alert Pin
    4. 8.4 Device Functional Modes
      1. 8.4.1 Averaging and Conversion Time Considerations
      2. 8.4.2 Filtering and Input Considerations
    5. 8.5 Programming
      1. 8.5.1 Programming the Calibration Register
      2. 8.5.2 Programming the INA230 Power Measurement Engine
        1. 8.5.2.1 Calibration Register and Scaling
      3. 8.5.3 Simple Current Shunt Monitor Usage (No Programming Necessary)
      4. 8.5.4 Default INA230 Settings
      5. 8.5.5 Bus Overview
        1. 8.5.5.1 Serial Bus Address
        2. 8.5.5.2 Serial Interface
      6. 8.5.6 Writing to and Reading From the I2C Serial Interface
        1. 8.5.6.1 High-Speed I2C Mode
      7. 8.5.7 SMBus Alert Response
    6. 8.6 Register Maps
      1. 8.6.1 Configuration Register (00h, Read/Write)
      2. 8.6.2 AVG Bit Settings [11:9]
      3. 8.6.3 VBUS CT Bit Settings [8:6]
      4. 8.6.4 VSH CT Bit Settings [5:3]
      5. 8.6.5 Mode Settings [2:0]
      6. 8.6.6 Data Output Register
        1. 8.6.6.1 Shunt Voltage Register (01h, Read-Only)
        2. 8.6.6.2 Bus Voltage Register (02h, Read-Only) (1)
        3. 8.6.6.3 Power Register (03h, Read-Only)
        4. 8.6.6.4 Current Register (04h, Read-Only)
        5. 8.6.6.5 Calibration Register (05h, Read/Write)
        6. 8.6.6.6 Mask/Enable Register (06h, Read/Write)
        7. 8.6.6.7 Alert Limit Register (07h, Read/Write)
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 High-Side Sensing Circuit Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RGT|16
  • DGS|10
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.5.1 Programming the Calibration Register

Figure 9-1 shows a nominal 10-A load that creates a differential voltage of 20 mV across a 2-mΩ shunt resistor. The bus voltage for the INA230 is measured at the external VBUS input pin, which in this example is connected to the IN– pin to measure the voltage level delivered to the load. For this example, the VBUS pin measures less than 12 V because the voltage at the IN– pin is 11.98 V as a result of the voltage drop across the shunt resistor.

For this example, assuming a maximum expected current of 15 A, the Current_LSB is calculated to be 457.7 μA/bit using Equation 2. Using a value for the Current_LSB of 500 μA/bit or 1 mA/bit would significantly simplify the conversion from the Current register (04h) and Power register (03h) to amperes and watts. For this example, a value of 1 mA/bit was chosen for the Current_LSB. Using this value for the Current_LSB does trade a small amount of resolution for having a simpler conversion process on the user side. Using Equation 1 in this example with a Current_LSB value of 1 mA/bit and a shunt resistor of 2 mΩ results in a Calibration register value of 2560, or A00h.

The Current register (04h) is then calculated by multiplying the decimal value of the Shunt Voltage register (01h) contents by the decimal value of the Calibration register and then dividing by 2048, as shown in Equation 3. For this example, the Shunt Voltage register contains a value of 8,000 (representing 20 mV), which is multiplied by the Calibration register value of 2560 and then divided by 2048 to yield a decimal value for the Current register (04h) of 10000, or 2710h. Multiplying this value by 1 mA/bit results in the original 10-A level stated in the example.

Equation 3. GUID-ABA85ACA-BB4B-49C7-A37B-937E45E641B9-low.gif

The LSB for the Bus Voltage register (02h) is a fixed 1.25 mV/bit, which means that the 11.98 V present at the VBUS pin results in a register value of 2570h, or a decimal equivalent of 9584. Note that the MSB of the Bus Voltage register (02h) is always zero because the VBUS pin is only able to measure positive voltages.

The Power register (03h) is then calculated by multiplying the decimal value of the Current register, 10000, by the decimal value of the Bus Voltage register (02h), 9584, and then dividing by 20,000, as defined in Equation 4. For this example, the result for the Power register (03h) is 12B8h, or a decimal equivalent of 4792. Multiplying this result by the power LSB (25 times the [1 × 10–3 Current_LSB]) results in a power calculation of (4792 × 25 mW/bit), or 119.82 W. The power LSB has a fixed ratio to the Current_LSB of 25. For this example, a programmed 1 mA/bit Current_LSB results in a power LSB of 25 mW/bit. This ratio is internally programmed to ensure that the scaling of the power calculation is within an acceptable range. A manual calculation for the power being delivered to the load would use a bus voltage of 11.98 V (12 VCM – 20 mV shunt drop) multiplied by the load current of 10 A to give a result of 119.8 W.

Equation 4. GUID-E0A4D3AF-67DE-42EB-BC46-5162F350743A-low.gif

Table 8-1 lists the steps for configuring, measuring, and calculating the values for current and power for this device.

Table 8-1 Calculating Current and Power(1)
STEPREGISTER NAMEADDRESSCONTENTSDECLSBVALUE
Step 1Configuration register00h4127h———
Step 2Shunt register01h1F40h80002.5 µV20 mV
Step 3Bus Voltage register02h2570h95841.25 mV11.98 V
Step 4Calibration register05hA00h2560——
Step 5Current register04h2710100001 mA10 A
Step 6Power register03h12B8h479225 mW119.82 W
(1) Conditions: Load = 10 A, VCM = 12 V, RSHUNT = 2 mΩ, and VVBUS = 12 V.