TIDUF82B August   2024  – May 2025 DRV8162 , INA241A , ISOM8710

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Reference Design Overview
    2. 1.2 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Hardware Design
        1. 2.2.1.1 Power Stage Gate Driver
          1. 2.2.1.1.1 Gate Driver
          2. 2.2.1.1.2 Protection Features
          3. 2.2.1.1.3 VGVDD Definition
          4. 2.2.1.1.4 Strap Functions
        2. 2.2.1.2 Power Stage FETs
          1. 2.2.1.2.1 VGS versus RDS(ON)
        3. 2.2.1.3 Phase Current and Voltage Sensing
          1. 2.2.1.3.1 Phase A and Phase B Current Sensing
          2. 2.2.1.3.2 Phase C Current Sensing
          3. 2.2.1.3.3 Voltage Sensing
        4. 2.2.1.4 Host Processor Interface
        5. 2.2.1.5 Gate Drive Shutdown Path
        6. 2.2.1.6 System Diagnostic Measurements
          1. 2.2.1.6.1 Temperature Measurement
        7. 2.2.1.7 System Power Supply
          1. 2.2.1.7.1 12V Rail
          2. 2.2.1.7.2 3.3V Rail
      2. 2.2.2 Software Design
    3. 2.3 Highlighted Products
      1. 2.3.1 DRV8162L
      2. 2.3.2 INA241A
      3. 2.3.3 AMC0106M05
      4. 2.3.4 TPSM861253
      5. 2.3.5 LMR38010
      6. 2.3.6 TMP6131
      7. 2.3.7 ISOM8710
  9. 3Hardware, Software Test Requirements and Test Results
    1. 3.1 Hardware Requirements
      1. 3.1.1 PCB Overview
      2. 3.1.2 Hardware Configuration
        1. 3.1.2.1 Prerequisites
        2. 3.1.2.2 Default Resistor and Jumper Configuration
        3. 3.1.2.3 Connector
          1. 3.1.2.3.1 Host Processor Interface
    2. 3.2 Test Setup
    3. 3.3 Test Results
      1. 3.3.1 Power Management
        1. 3.3.1.1 Power Up
        2. 3.3.1.2 Power Down
      2. 3.3.2 Gate Voltage and Phase Voltage
        1. 3.3.2.1 20 VDC
        2. 3.3.2.2 48 VDC
        3. 3.3.2.3 60 VDC
      3. 3.3.3 Digital PWM and Gate Voltage
      4. 3.3.4 Phase-Current Measurements
      5. 3.3.5 System Test Results
        1. 3.3.5.1 Thermal Analysis
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Tools and Software
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Authors
  12. 6Revision History
2.2.1.3.3 Voltage Sensing

The DC input voltage VIN and the three phase output voltages of the drive are measured in this design. The maximum input voltage can be up to 80V and is limited by the LMR38010 buck converter, which is used to generate the 12V voltage rail for the gate drivers.

In this design, the voltage sense dividers are set to support a maximum sense voltage of 80V, which is enough for the rated VIN of 48V for the system.

Figure 2-6 shows a schematic view of the VIN voltage measurement.

TIDA-010956 TIDA-010956 VIN Voltage Sense Circuit Figure 2-6 TIDA-010956 VIN Voltage Sense Circuit

Equation 3 is used for the calculation.

Equation 3. R 6 = R 3 × V OUT V IN - V OUT = 110 k Ω × 3 . 3 V 80 V - 3 . 3 V = 4,733 Ω

where

  • R3 is chosen as 110kΩ

For each voltage divider, a low-pass filter is adopted; such as in this specific channel with C3.

For the phase voltages and the VIN voltage measurements, put these values into Equation 3: VIN = 80V,
Vout = 3.3V, R3 = 110kΩ. This makes R6 = 4733Ω. A 4.7kΩ, 1% resistor is chosen.