SLYY234 December   2024 AMC0106M05 , AMC0106M25 , AMC0136 , AMC0311D , AMC0311S , AMC0386 , AMC0386-Q1 , AMC1100 , AMC1106M05 , AMC1200 , AMC1200-Q1 , AMC1202 , AMC1203 , AMC1204 , AMC1211-Q1 , AMC1300 , AMC1300B-Q1 , AMC1301 , AMC1301-Q1 , AMC1302-Q1 , AMC1303M2510 , AMC1304L25 , AMC1304M25 , AMC1305M25 , AMC1305M25-Q1 , AMC1306M05 , AMC1306M25 , AMC1311 , AMC1311-Q1 , AMC131M03 , AMC1336 , AMC1336-Q1 , AMC1350 , AMC1350-Q1 , AMC23C12 , AMC3301 , AMC3330 , AMC3330-Q1

 

  1.   1
  2.   Introduction
  3.   Introduction to Isolated Signal Chain
    1.     Comparing Isolated Amplifiers and Isolated Modulators
      1.      Abstract
      2.      Introduction to Isolated Amplifiers
      3.      Introduction to Isolated Modulators
      4.      Performance Comparison Between Isolated Amplifiers and Isolated Modulators
      5.      Isolated Modulators in Traction Inverters
      6.      Isolated Amplifier and Modulator Recommendations
      7.      Conclusion
    2.     TI’s First Isolated Amplifiers With Ultra-Wide Creepage and Clearance
      1.      Application Brief
  4.   Selection Trees
  5.   Current Sensing
    1.     Shunt Resistor Selection for Isolated Data Converters
      1.      17
    2.     Design considerations for isolated current sensing
      1.      19
      2.      Conclusion
      3.      References
      4.      Related Websites
    3.     Isolated Current-Sensing Circuit With ±50-mV Input and Single-Ended Output
      1.      24
    4.     Isolated Current-Sensing Circuit With ±50-mV Input and Differential Output
      1.      26
    5.     Isolated Current-Sensing Circuit With ±250-mV Input Range and Single-Ended Output Voltage
      1.      Design Goals
      2.      Design Description
      3.      Design Notes
      4.      Design Steps
      5.      Design Simulations
      6.      DC Simulation Results
      7.      Closed-Loop AC Simulation Results
      8.      Transient Simulation Results
      9.      Design References
      10.      Design Featured Isolated Amplifier
      11.      Design Alternate Isolated Amplifier
    6.     Isolated current-measurement circuit with ±250-mV input and differential output
      1.      Design Goals
      2.      Design Description
      3.      Design Notes
      4.      Design Steps
      5.      Design Simulations
      6.      DC Simulation Results
      7.      Closed Loop AC Simulation Results
      8.      Transient Simulation Results
      9.      Design References
      10.      Design Featured Op Amp
      11.      Design Alternate Op Amp
    7.     Isolated Overcurrent Protection Circuit
      1.      52
    8.     Interfacing a Differential-Output (Isolated) Amp to a Single-Ended Input ADC
      1.      54
    9.     Utilizing AMC3311 to Power AMC23C11 for Isolated Sensing and Fault Detection
      1.      Application Brief
    10.     Isolated Current-Sensing Circuit With Front-End Gain Stage
      1.      58
    11.     Accuracy Comparison of Isolated Shunt and Closed-Loop Current Sensing
      1.      60
  6.   Voltage Sensing
    1.     Maximizing Power Conversion and Motor Control Efficiency With Isolated Voltage Sensing
      1.      63
      2.      Solutions for high-voltage sensing
      3.      Integrated resistor devices
      4.      Single-ended output devices
      5.      Integrated isolated voltage-sensing use cases
      6.      Conclusion
      7.      Additional resources
    2.     Increased Accuracy and Performance with Integrated High Voltage Resistor Isolated Amplifiers and Modulators
      1.      Abstract
      2.      Introduction
      3.      High Voltage Resistor Isolated Amplifiers and Modulators Advantages
        1.       Space Savings
        2.       Improved Temperature and Lifetime Drift of Integrated HV Resistors
        3.       Accuracy Results
        4.       Fully Integrated Resistors vs. Additional External Resistor Example
        5.       Device Selection Tree and AC/DC Common Use Cases
      4.      Summary
      5.      References
    3.     Isolated Amplifiers With Differential, Single-Ended Fixed Gain and Ratiometric Outputs for Voltage Sensing Applications
      1.      Abstract
      2.      Introduction
      3.      Overview of Differential, Single-Ended Fixed Gain and Ratiometric Outputs
        1.       Isolated Amplifiers with Differential Output
        2.       Isolated Amplifiers With Single-Ended, Fixed-Gain Output
        3.       Isolated Amplifiers With Single-Ended, Ratiometric Output
      4.      Application Examples
        1.       Product Selection Tree
      5.      Summary
      6.      References
    4.     Isolated Voltage-Measurement Circuit With ±250-mV Input and Differential Output
      1.      93
    5.     Split-Tap Connection for Line-to-Line Isolated Voltage Measurement Using AMC3330
      1.      95
    6.     ±12V Voltage Sensing Circuit With an Isolated Amplifier and Pseudo-Differential Input SAR ADC
      1.      97
    7.     ±12-V voltage sensing circuit with an isolated amplifier and differential input SAR ADC
      1.      99
    8.     Isolated Undervoltage and Overvoltage Detection Circuit
      1.      101
    9.     Isolated Zero-Cross Detection Circuit
      1.      103
    10.     ±480V Isolated Voltage-Sensing Circuit With Differential Output
      1.      105
  7.   EMI Performance
    1.     Best in Class Radiated Emissions EMI Performance with Isolated Amplifiers
      1.      Best in Class Radiated Emissions EMI Performance with Isolated Amplifiers
      2.      Introduction
      3.      Current Generation of Texas Instruments Isolated Amplifiers Radiated Emissions Performance
      4.      Previous Generations of Texas Instruments Isolated Amplifiers Radiated Emissions Performance
      5.      Conclusion
      6.      References
    2.     Best Practices to Attenuate AMC3301 Family Radiated Emissions EMI
      1.      Abstract
      2.      Introduction
      3.      Effects of Input Connections on AMC3301 Family Radiated Emissions
      4.      Attenuating AMC3301 Family Radiated Emissions
        1.       Ferrite Beads and Common Mode Chokes
        2.       PCB Schematics and Layout Best Practices for AMC3301 Family
      5.      Using Multiple AMC3301 Devices
        1.       Device Orientation
        2.       PCB Layout Best Practices for Multiple AMC3301
      6.      Conclusion
      7.      AMC3301 Family Table
  8.   End Equipment
    1.     Comparing Shunt- and Hall-Based Isolated Current-Sensing Solutions in HEV/EV
      1.      128
    2.     Design Considerations for Current Sensing in DC EV Charging Applications
      1.      Abstract
      2.      Introduction
        1.       DC Charging Station for Electric Vehicles
        2.       Current-Sensing Technology Selection and Equivalent Model
          1.        Sensing of the Current With Shunt-Based Solution
          2.        Equivalent Model of the Sensing Technology
      3.      Current Sensing in AC/DC Converters
        1.       Basic Hardware and Control Description of AC/DC
          1.        AC Current Control Loops
          2.        DC Voltage Control Loop
        2.       Point A and B – AC/DC AC Phase-Current Sensing
          1.        Impact of Bandwidth
            1.         Steady State Analysis: Fundamental and Zero Crossing Currents
            2.         Transient Analysis: Step Power and Voltage Sag Response
          2.        Impact of Latency
            1.         Fault Analysis: Grid Short-Circuit
          3.        Impact of Gain Error
            1.         Power Disturbance in AC/DC Caused by Gain Error
            2.         AC/DC Response to Power Disturbance Caused by Gain Error
          4.        Impact of Offset
        3.       Point C and D – AC/DC DC Link Current Sensing
          1.        Impact of Bandwidth on Feedforward Performance
          2.        Impact of Latency on Power Switch Protection
          3.        Impact of Gain Error on Power Measurement
            1.         Transient Analysis: Feedforward in Point D
          4.        Impact of Offset
        4.       Summary of Positives and Negatives at Point A, B, C1/2 and D1/2 and Product Suggestions
      4.      Current Sensing in DC/DC Converters
        1.       Basic Operation Principle of Isolated DC/DC Converter With Phase-Shift Control
        2.       Point E, F - DC/DC Current Sensing
          1.        Impact of Bandwidth
          2.        Impact of Gain Error
          3.        Impact of Offset Error
        3.       Point G - DC/DC Tank Current Sensing
        4.       Summary of Sensing Points E, F, and G and Product Suggestions
      5.      Conclusion
      6.      References
    3.     Using isolated comparators for fault detection in electric motor drives
      1.      Introduction
      2.      Introduction to electric motor drives
      3.      Understanding fault events in electric motor drives
      4.      Achieving reliable detection and protection in electric motor drives
      5.      Use case No. 1: Bidirectional in-phase overcurrent detection
      6.      Use case No. 2: DC+ overcurrent detection
      7.      Use case No. 3: DC– overcurrent or short-circuit detection
      8.      Use case No. 4: DC-link (DC+ to DC–) overvoltage and undervoltage detection
      9.      Use case No. 5: IGBT module overtemperature detection
    4.     Discrete DESAT for Opto-Compatible Isolated Gate Driver UCC23513 in Motor Drives
      1.      Abstract
      2.      Introduction
      3.      System Challenge on Isolated Gate Drivers With Integrated DESAT
      4.      System Approach With UCC23513 and AMC23C11
        1.       System Overview and Key Specification
        2.       Schematic Design
          1.        Circuit Schematic
          2.        Configure VCE(DESAT) Threshold and DESAT Bias Current
          3.        DESAT Blanking Time
          4.        DESAT Deglitch Filter
        3.       Reference PCB Layout
      5.      Simulation and Test Results
        1.       Simulation Circuit and Results
          1.        Simulation Circuit
          2.        Simulation Results
        2.       Test Results With 3-Phase IGBT Inverter
          1.        Brake IGBT Test
          2.        Test Results on a 3-Phase Inverter With Phase to Phase Short
      6.      Summary
      7.      References
    5.     Isolated voltage sensing in AC motor drives
      1.      Introduction
      2.      Conclusion
      3.      References
    6.     Achieving High-Performance Isolated Current and Voltage Sensing in Server PSUs
      1.      Application Brief
  9.   Additional Reference Designs/Circuits
    1.     Designing a Bootstrap Charge-Pump Power Supply for an Isolated Amplifier
      1.      Abstract
      2.      Introduction
      3.      Bootstrap Power Supply Design
        1.       Selection of Charge Pump Capacitor
        2.       Simulation in TINA-TI
        3.       Hardware Test with AMC1311-Q1
      4.      Summary
      5.      Reference
    2.     Clock Edge Delay Compensation With Isolated Modulators Digital Interface to MCUs
      1.      Abstract
      2.      Introduction
      3.      Design Challenge With Digital Interface Timing Specifications
      4.      Design Approach With Clock Edge Delay Compensation
        1.       Clock Signal Compensation With Software Configurable Phase Delay
        2.       Clock Signal Compensation With Hardware Configurable Phase Delay
        3.       Clock Signal Compensation by Clock Return
        4.       Clock Signal Compensation by Clock Inversion at the MCU
      5.      Test and Validation
        1.       Test Equipment and Software
        2.       Testing of Clock Signal Compensation With Software Configurable Phase Delay
          1.        Test Setup
          2.        Test Measurement Results
        3.       Testing of Clock Signal Compensation by Clock Inversion at MCU
          1.        Test Setup
          2.        Test Measurement Results
            1.         Test Result – No Clock Inversion of Clock Input at GPIO123
            2.         Test Result – Clock Inversion of Clock Input at GPIO123
        4.       Digital Interface Timing Validation by Calculation Tool
          1.        Digital Interface With No Compensation Method
          2.        Commonly Used Method - Reduction of the Clock Frequency
          3.        Clock Edge Compensation With Software Configurable Phase Delay
      6.      Conclusion
      7.      References
    3.     Utilizing AMC3311 to Power AMC23C11 for Isolated Sensing and Fault Detection
      1.      Application Brief

Application Brief

Introduction

Fault-detection is essential in applications including motor drives, servo drives, onboard chargers (OBCs), string inverters, and micro inverters. Separating the high voltage domain and the low voltage domain across an isolation barrier allows the system to operate at different common-mode voltages. The high voltage domain performs a function while the low voltage domain controls equipment. This prevents both electrical damage to the low voltage circuitry and harm to users. Detecting faults such as overvoltage is required when operating at high common-mode voltages. This document highlights how the AMC3311 can offer high-side supply current from HLDO_OUT to power the high voltage domain of the AMC23C11 isolated comparator for a compact fault detection design.

The AMC3311 is a precision, reinforced, isolated amplifier. This device has a 0-2 V input voltage range, which is an option for precision isolated DC voltage measurements that drive the control loop. This device features an integrated DC/DC converter that supports high-side supply current for auxiliary circuitry of 4 mA. This allows for single-supply operation from the low-side to high-side of the device for both the feedback measurement of the AMC3311 and the overvoltage fault detection of the AMC23C11. The AMC23C11 is a fast response, reinforced, isolated comparator. The device can be used for rapid overcurrent or overvoltage sensing with an adjustable trip threshold. The device requires a high-side supply current of 2.7 mA. The AMC3311 is the first isolated amplifier with an integrated DC/DC converter to enable the two devices to work as a pair for applications that require a precision isolated amplifier for control functions and a fast-acting comparator for overcurrent or overvoltage protection.

AMC3311 used to power AMC23C11

The AMC3311 offers an isolated power supply capable of providing up to 4 mA through the HLDO_OUT pin for connected components that require a high-side supply. This feature directly allows the use of higher performance isolated comparators such as the AMC23C11.

The available supply current from the AMC3311 allows a wider range of companion devices to be used with the isolated amplifier. Figure 20 shows an example schematic of how to use the AMC3311 to power the high side of the AMC23C11. In the schematic, HLDO_OUT at pin five on the AMC3311 shows a trace that extends to VDD1 at pin one of the AMC23C11. The isolated comparator compares the input voltage to the reference voltage at pin three. The device pulls down the open-drain output if the input voltage exceeds the threshold established as the reference voltage. The threshold voltage can be adjusted by modifying the value of the reference resistor in relation to the internal 100-μA current source.

Additionally, the AMC23C11 has a 1.4-V margin overhead voltage. The threshold voltage cannot be higher than the difference of the 3.2-V input and 1.4-V margin (1.8 V.) A resistor is placed between REF and GND1 to define the trip voltage as 1.07 V. As a result, this overhead requirement limits the threshold voltage on the isolated comparator to be lower than the true cutoff voltage seen on the amplifier. For example, when the true cutoff voltage is 2.14 V on the amplifier, the isolated comparator cannot monitor the voltage because the voltage exceeds the bounds set by the margin overhead voltage. As a result, RSNS is separated into two equal resistors (RSNS1 and RSNS2) to define the cutoff voltage to be proportionately half of the voltage that the AMC3311 requires. Instead, the AMC23C11 reads 1.07 V as the reference voltage.

Figure 21 shows an example of a PCB layout example that routes the devices in combination.

AMC3311 and AMC23C11 Schematic Figure 164 AMC3311 and AMC23C11 Schematic
AMC3311 and AMC23C11 PCB Layout Figure 165 AMC3311 and AMC23C11 PCB Layout

AMC23C11 used for overvoltage detection

Figure 22 and Figure 23 show the overvoltage response times in the AMC3311 and the AMC23C11, respectively. Using a 3.2-V power supply, the input signal (CH4) shows the voltage rise above the 1.07 V overvoltage threshold.

The response time on the AMC3311, VOUTP (CH2), and VOUTN channels (CH1) is 2.906 μs, while the response time on the AMC23C11, OUT (CH3), is 314.015 ns. The amplifier takes greater than nine times the length the isolated comparator takes to detect overvoltage. This time delay can be too long for low latency applications. To supplement the AMC3311 amplifier, the isolated comparator can be used to prevent an overvoltage, as the comparator quickly detects voltages higher than the set threshold. This notifies the controller to shut down all affected electronics, which offers increased safety and reliability in high voltage applications.

AMC3311 Overvoltage Response Timing Waveform Figure 166 AMC3311 Overvoltage Response Timing Waveform
AMC23C11 Overvoltage Response Timing Waveform Figure 167 AMC23C11 Overvoltage Response Timing Waveform

Conclusion

The AMC3311 is an isolated amplifier with a high-side current supply that can be leveraged to power auxiliary sensing circuits. The device can power external devices up to 4 mA on the high-side, and is compatible with high-speed isolated comparators such as the AMC23C11. This comparator offers the advantage of a significantly faster response time to enable overvoltage protection. Using the AMC3311 and AMC23C11 together can be a useful option for voltage and current sensing applications.