ZHCSOF7B september   2022  – june 2023 TPS25990

PRODUCTION DATA  

  1.   1
  2. 特性
  3. 应用
  4. 说明
  5. Revision History
  6. 说明(续)
  7. Pin Configuration and Functions
  8. 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  Logic Interface DC Characteristics
    7. 7.7  Telemetry
    8. 7.8  PMBus Interface Timing Characteristics
    9. 7.9  External EEPROM Interface Timing Characteristics
    10. 7.10 Timing Requirements
    11. 7.11 Switching Characteristics
    12. 7.12 Typical Characteristics
  9. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Undervoltage Protection
      2. 8.3.2  Insertion Delay
      3. 8.3.3  Overvoltage Protection
      4. 8.3.4  Inrush Current, Overcurrent, and Short-Circuit Protection
        1. 8.3.4.1 Slew rate (dVdt) and Inrush Current Control
          1. 8.3.4.1.1 Start-Up Timeout
        2. 8.3.4.2 Steady-State Overcurrent Protection (Circuit-Breaker)
        3. 8.3.4.3 Active Current Limiting During Start-Up
        4. 8.3.4.4 Short-Circuit Protection
      5. 8.3.5  Single Point Failure Mitigation
        1. 8.3.5.1 IMON Pin Single Point Failure
        2. 8.3.5.2 ILIM Pin Single Point Failure
        3. 8.3.5.3 IREF Pin Single Point Failure
      6. 8.3.6  Analog Load Current Monitor (IMON)
      7. 8.3.7  Overtemperature Protection
      8. 8.3.8  Analog Junction Temperature Monitor (TEMP)
      9. 8.3.9  FET Health Monitoring
      10. 8.3.10 General Purpose Digital Input/Output Pins
        1. 8.3.10.1 Fault Response and Indication (FLT)
        2. 8.3.10.2 Power Good Indication (PG)
        3. 8.3.10.3 Parallel Device Synchronization (SWEN)
      11. 8.3.11 Stacking Multiple eFuses for Unlimited Scalability
        1. 8.3.11.1 Current Balancing During Start-Up
      12. 8.3.12 General Purpose Comparators
      13. 8.3.13 Output Discharge
      14. 8.3.14 PMBus® Digital Interface
        1. 8.3.14.1  PMBus® Device Addressing
        2. 8.3.14.2  SMBus Protocol
        3. 8.3.14.3  SMBus™ Message Formats
        4. 8.3.14.4  Packet Error Checking
        5. 8.3.14.5  Group Commands
        6. 8.3.14.6  SMBus™ Alert Response Address (ARA)
        7. 8.3.14.7  PMBus® Commands
          1. 8.3.14.7.1 Detailed Descriptions of PMBus® Commands
            1. 8.3.14.7.1.1  OPERATION (01h, Read/Write Byte)
            2. 8.3.14.7.1.2  CLEAR_FAULTS (03h, Send Byte)
            3. 8.3.14.7.1.3  RESTORE_FACTORY_DEFAULTS (12h, Send Byte)
            4. 8.3.14.7.1.4  STORE_USER_ALL (15h, Send Byte)
            5. 8.3.14.7.1.5  RESTORE_USER_ALL (16h, Send Byte)
            6. 8.3.14.7.1.6  BB_ERASE (F5h, Send Byte)
            7. 8.3.14.7.1.7  FETCH_BB_EEPROM (F6h, Send Byte)
            8. 8.3.14.7.1.8  POWER_CYCLE (D9h, Send Byte)
            9. 8.3.14.7.1.9  MFR_WRITE_PROTECT (F8h, Read/Write Byte)
            10. 8.3.14.7.1.10 CAPABILITY (19h, Read Byte)
            11. 8.3.14.7.1.11 STATUS_BYTE (78h, Read Byte)
            12. 8.3.14.7.1.12 STATUS_WORD (79h, Read Word)
            13. 8.3.14.7.1.13 STATUS_OUT (7Ah, Read Byte)
            14. 8.3.14.7.1.14 STATUS_IOUT (7Bh, Read Byte)
            15. 8.3.14.7.1.15 STATUS_INPUT (7Ch, Read Byte)
            16. 8.3.14.7.1.16 STATUS_TEMP (7Dh, Read Byte)
            17. 8.3.14.7.1.17 STATUS_CML (7Eh, Read Byte)
            18. 8.3.14.7.1.18 STATUS_MFR_SPECIFIC (80h, Read Byte)
            19. 8.3.14.7.1.19 STATUS_MFR_SPECIFIC_2 (F3h, Read Word)
            20. 8.3.14.7.1.20 PMBUS_REVISION (98h, Read Byte)
            21. 8.3.14.7.1.21 MFR_ID (99h, Block Read)
            22. 8.3.14.7.1.22 MFR_MODEL (9Ah, Block Read)
            23. 8.3.14.7.1.23 MFR_REVISION (9Bh, Block Read)
            24. 8.3.14.7.1.24 READ_VIN (88h, Read Word)
            25. 8.3.14.7.1.25 READ_VOUT (8Bh, Read Word)
            26. 8.3.14.7.1.26 READ_IIN (89h, Read Word)
            27. 8.3.14.7.1.27 READ_TEMPERATURE_1 (8Dh, Read Word)
            28. 8.3.14.7.1.28 READ_VAUX (D0h, Read Word)
            29. 8.3.14.7.1.29 READ_PIN (97h, Read Word)
            30. 8.3.14.7.1.30 READ_EIN (86h, Block Read)
            31. 8.3.14.7.1.31 READ_VIN_AVG (DCh, Read Word)
            32. 8.3.14.7.1.32 READ_VIN_MIN (D1h, Read Word)
            33. 8.3.14.7.1.33 READ_VIN_PEAK (D2h, Read Word)
            34. 8.3.14.7.1.34 READ_VOUT_AVG (DDh, Read Word)
            35. 8.3.14.7.1.35 READ_VOUT_MIN (DAh, Read Word)
            36. 8.3.14.7.1.36 READ_IIN_AVG (DEh, Read Word)
            37. 8.3.14.7.1.37 READ_IIN_PEAK (D4h, Read Word)
            38. 8.3.14.7.1.38 READ_TEMP_AVG (D6h, Read Word)
            39. 8.3.14.7.1.39 READ_TEMP_PEAK (D7h, Read Word)
            40. 8.3.14.7.1.40 READ_PIN_AVG (DFh, Read Word)
            41. 8.3.14.7.1.41 READ_PIN_PEAK (D5h, Read Word)
            42. 8.3.14.7.1.42 READ_SAMPLE_BUF (D8h, Block Read)
            43. 8.3.14.7.1.43 READ_BB_RAM (FDh, Block Read)
            44. 8.3.14.7.1.44 READ_BB_EEPROM (F4h, Block Read)
            45. 8.3.14.7.1.45 BB_TIMER (FAh, Read Byte)
            46. 8.3.14.7.1.46 PMBUS_ADDR (FBh, Read/Write Byte)
            47. 8.3.14.7.1.47 VIN_UV_WARN (58h, Read/Write Word)
            48. 8.3.14.7.1.48 VIN_UV_FLT (59h, Read/Write Word)
            49. 8.3.14.7.1.49 VIN_OV_WARN (57h, Read/Write Word)
            50. 8.3.14.7.1.50 VIN_OV_FLT (55h, Read/Write Word)
            51. 8.3.14.7.1.51 VOUT_UV_WARN (43h, Read/Write Word)
            52. 8.3.14.7.1.52 VOUT_PGTH (5Fh, Read/Write Word)
            53. 8.3.14.7.1.53 OT_WARN (51h, Read/Write Word)
            54. 8.3.14.7.1.54 OT_FLT (4Fh, Read/Write Word)
            55. 8.3.14.7.1.55 PIN_OP_WARN (6Bh, Read/Write Word)
            56. 8.3.14.7.1.56 IIN_OC_WARN (5Dh, Read/Write Word)
            57. 8.3.14.7.1.57 VIREF (E0h, Read/Write Byte)
            58. 8.3.14.7.1.58 GPIO_CONFIG_12 (E1h, Read/Write Byte)
            59. 8.3.14.7.1.59 GPIO_CONFIG_34 (E2h, Read/Write Byte)
            60. 8.3.14.7.1.60 ALERT_MASK (DBh, Read/Write Word)
            61. 8.3.14.7.1.61 FAULT_MASK (E3h, Read/Write Word)
            62. 8.3.14.7.1.62 DEVICE_CONFIG (E4h, Read/Write Word)
            63. 8.3.14.7.1.63 BB_CONFIG (E5h, Read/Write Byte)
            64. 8.3.14.7.1.64 OC_TIMER (E6h, Read/Write Byte)
            65. 8.3.14.7.1.65 RETRY_CONFIG (E7h, Read/Write Byte)
            66. 8.3.14.7.1.66 ADC_CONFIG_1 (E8h, Read/Write Byte)
            67. 8.3.14.7.1.67 ADC_CONFIG_2 (E9h, Read/Write Byte)
            68. 8.3.14.7.1.68 PK_MIN_AVG (EAh, Read/Write Byte)
            69. 8.3.14.7.1.69 VCMPxREF (EBh, Read/Write Byte)
            70. 8.3.14.7.1.70 PSU_VOLTAGE (ECh, Read/Write Byte)
            71. 8.3.14.7.1.71 CABLE_DROP (EDh, Read/Write Byte)
            72. 8.3.14.7.1.72 GPDAC1 (F0h, Read/Write Byte)
            73. 8.3.14.7.1.73 GPDAC2 (F1h, Read/Write Byte)
            74. 8.3.14.7.1.74 INS_DLY (F9h, Read/Write Byte)
        8. 8.3.14.8  Analog-to-digital Converter
        9. 8.3.14.9  Digital-to-analog Converters
        10. 8.3.14.10 DIRECT format Conversion
        11. 8.3.14.11 Blackbox Fault Recording
    4. 8.4 Device Functional Modes
  10. Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Single Device, Standalone Operation
      2. 9.1.2 Multiple Devices, Parallel Connection
      3. 9.1.3 Multiple Devices, Independent Operation (Multi-zone)
    2. 9.2 Typical Application: 12-V, 4-kW Power Path Protection with PMBus® Interface in Datacenter Servers
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Performance Plots
    3. 9.3 Best Design Practices
    4. 9.4 Power Supply Recommendations
      1. 9.4.1 Transient Protection
      2. 9.4.2 Output Short-Circuit Measurements
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 接收文档更新通知
    3. 10.3 支持资源
    4. 10.4 Trademarks
    5. 10.5 静电放电警告
    6. 10.6 术语表
  12. 11Mechanical, Packaging, and Orderable Information

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机械数据 (封装 | 引脚)
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订购信息

Stacking Multiple eFuses for Unlimited Scalability

For systems needing higher current than supported by a single TPS25990, it is possible to connect TPS25990 in parallel with one or more TPS25985x devices to deliver the desired total system current. Conventional eFuses do not share current evenly between themselves during steady-state due to mismatches in their path resistances (which includes the individual device RDSON variation from part to part, as well as the parasitic PCB trace resistance). This fact can lead to multiple problems in the system:

  1. Some devices always carry higher current as compared to other devices, which can result in accelerated failures in those devices and an overall reduction in system operational lifetime.

  2. As a result, thermal hotspots form on the board, devices, traces, and vias carrying higher current, leading to reliability concerns for the PCB. In addition, this problem makes thermal modeling and board thermal management more challenging for designers.

  3. The devices carrying higher current can hit their individual circuit-breaker threshold prematurely even while the total system load current is lower than the overall circuit-breaker threshold. This action can lead to false tripping of the eFuse chain during normal operation. This has the effect of lowering the current-carrying capability of the parallel chain. In other words, the current rating of the parallel eFuse chain needs to be de-rated as compared to the sum of the current ratings of the individual eFuses. This de-rating factor is a function of the path resistance mismatch, the number of devices in parallel, and the individual eFuse circuit-breaker accuracy.

The need for de-rating has an adverse impact on the system design. The designer is forced to make one of these trade-offs:

  1. Limit the operating load current of the system to below the derated overcurrent threshold of the eFuse chain. Essentially, it means lower platform capabilities than are supported by the power supply (PSU).

  2. Increase the overall circuit-breaker threshold to allow the desired system load current to pass through without tripping. As a consequence, the power supply (PSU) must be oversized to deliver higher currents during faults to account for the degradation of the overall circuit-breaker accuracy.

In either case, the system suffers from poor power supply utilization, which can mean sub-optimal system throughput or increased installation and operating costs, or both.

The TPS25990 and TPS25985x devices use a proprietary technique to address these problems and provide unlimited scalability of the solution by paralleling as many eFuses as needed. This is incorporated without significant current imbalance or any degradation in accuracy.

For this scheme to work correctly, the devices must be connected in the following manner:

  • The SWEN pins of all the devices are connected together.

  • The IMON pins of all the devices need to be connected together. The RIMON resistor value on the combined IMON pin can be calculated using Equation 11.

    Equation 11. RIMON=VIREFGIMON×IOCPTOTAL

  • The IREF pins of all the devices need to be connected together. The TPS25990 generates the VIREF reference voltage for the whole chain using its internal DAC which can be programmed using PMBus® writes to the VIREF register. This allows the overcurrent protection thresholds to be dynamically adjusted during system operation. It is also possible to drive the IREF pin using a low impedance external precision voltage reference.

  • The start-up current limit and active current sharing threshold for each device is set independently using the ILIM pin. The RILIM value for the TPS25990 must be selected based on the following equation.

    Equation 12. RILIM(25990) =1.1 ×4N-1×RIMON 9 

    The RILIM value for each TPS25985x must be selected based on the following equation.

    Equation 13. RILIM(25985) =1.1 ×4N-1×RIMON 12 

    Where N = Number of devices in parallel chain (1 × TPS25990 + (N - 1) × TPS25985)

Note:
  1. The active current sharing scheme is engaged when the current through any eFuse while in steady-state exceeds the individual current sharing threshold set by the RILIM based on Equation 14.

    Equation 14. RILIM=1.1×VIREF3×GILIM×ILIMACS

  2. The active current sharing scheme is disengaged when the total system current exceeds the system overcurrent (circuit-breaker) threshold (IOCP(TOTAL)).