SLUSB56B November   2012  – April 2019 TPS53819A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Application
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Enable and Soft-Start
      2. 7.3.2  Adaptive On-Time Control
      3. 7.3.3  Zero Crossing Detection
      4. 7.3.4  Output Discharge Control
      5. 7.3.5  Low-Side Driver
      6. 7.3.6  High-Side Driver
      7. 7.3.7  Power Good
      8. 7.3.8  Current Sense and Overcurrent Protection
      9. 7.3.9  Overvoltage and Undervoltage Protection
      10. 7.3.10 Out-of-Bound Protection
      11. 7.3.11 UVLO Protection
      12. 7.3.12 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Light-Load Condition in Auto-Skip Operation (Eco-mode)
      2. 7.4.2 Forced Continuous Conduction Mode
      3. 7.4.3 D-CAP2™ Mode
    5. 7.5 Programming
      1. 7.5.1 PMBus General Descriptions
      2. 7.5.2 PMBus Slave Address Selection
      3. 7.5.3 PMBus Address Selection
      4. 7.5.4 Supported Formats
        1. 7.5.4.1 Direct Format: Write
        2. 7.5.4.2 Combined Format: Read
        3. 7.5.4.3 Stop-Separated Reads
      5. 7.5.5 Supported PMBus Commands
      6. 7.5.6 Unsupported PMBus Commands
    6. 7.6 Register Maps
      1. 7.6.1  OPERATION [01h] (R/W Byte)
      2. 7.6.2  ON_OFF_CONFIG [02h] (R/W Byte)
      3. 7.6.3  WRITE_PROTECT [10h] (R/W Byte)
      4. 7.6.4  CLEAR_FAULTS [03h] (Send Byte)
      5. 7.6.5  STORE_DEFAULT_ALL [11h] (Send Byte)
      6. 7.6.6  RESTORE_DEFAULT_ALL [12h] (Send Byte)
      7. 7.6.7  STATUS_WORD [79h] (Read Word)
      8. 7.6.8  CUSTOM_REG (MFR_SPECIFIC_00) [D0h] (R/W Byte)
      9. 7.6.9  DELAY_CONTROL (MFR_SPECIFIC_01) [D1h] (R/W Byte)
      10. 7.6.10 MODE_SOFT_START_CONFIG (MFR_SPECIFIC_02) [D2h] (R/W Byte)
      11. 7.6.11 FREQUENCY_CONFIG (MFR_SPECIFIC_03) [D3h] (R/W Byte)
      12. 7.6.12 VOUT_ADJUSTMENT (MFR_SPECIFIC_04) [D4h] (R/W Byte)
      13. 7.6.13 Output Voltage Fine Adjustment Soft Slew Rate
      14. 7.6.14 VOUT_MARGIN (MFR_SPECIFIC_05) [D5h] (R/W Byte)
      15. 7.6.15 Output Voltage Margin Adjustment Soft-Slew Rate
      16. 7.6.16 UVLO_THRESHOLD (MFR_SPECIFIC_06) [D6h]
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1  Custom Design With WEBENCH® Tools
        2. 8.2.2.2  Switching Frequency
        3. 8.2.2.3  Inductor (L1)
        4. 8.2.2.4  Output Capacitors (C10, C11, C12, C13, C14)
        5. 8.2.2.5  Input Capacitors (C1, C2, C3, C4, C5)
        6. 8.2.2.6  MOSFET (Q1, Q2)
        7. 8.2.2.7  VREG Bypass Capacitor (C18)
        8. 8.2.2.8  VDD Bypass Capacitor (C19)
        9. 8.2.2.9  VBST Capacitor (C7)
        10. 8.2.2.10 Snubber (C8 and R9)
        11. 8.2.2.11 Feedback Resistance, RFBH and RFBL (R17 and R18)
        12. 8.2.2.12 Overcurrent Limit (OCL) Setting Resistance (R10)
        13. 8.2.2.13 PMBus Device Address (R3 and R4)
        14. 8.2.2.14 PGOOD Pullup Resistor (R2)
        15. 8.2.2.15 SCL and SDA Pulldown Resistors (R14 and R15)
        16. 8.2.2.16 PMBus Pullup Resistors
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Custom Design With WEBENCH® Tools
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.8 Current Sense and Overcurrent Protection

TPS53819A has cycle-by-cycle overcurrent limiting control. The inductor current is monitored during the OFF state and the controller maintains the OFF state during the period when inductor current is larger than the overcurrent trip level. In order to provide both good accuracy and cost effective solution, TPS53819A supports temperature compensated MOSFET on-resistance (RDS(on)) sensing. The TRIP pin should be connected to GND through the trip voltage setting resistor, RTRIP. The TRIP terminal sources ITRIP current, which is 10 μA typically at room temperature, and the trip level is set to the OCL trip voltage VTRIP as shown in Equation 4. Note that the VTRIP is limited up to approximately 3 V internally.

Equation 4. TPS53819A q_vtrip_lusau9.gif

The inductor current is monitored by the voltage between GND pin and SW pin so that SW pin should be properly connected to the drain terminal of the low-side MOSFET. The TRIP current has a 4700-ppm/°C temperature slope to compensate the temperature dependency of the on-resistance. The device uses the GND pin as the positive current sensing node. As the comparison occurs during the OFF state, VTRIP sets the valley level of the inductor current. Thus, the average load current at the overcurrent threshold, IOCP, is calculated as shown in Equation 5.

Equation 5. TPS53819A q_iocp_lusau9.gif

In an overcurrent condition, the load current exceeds the inductor current delivered to the output capacitor, thus the output voltage tends to fall. Eventually, it crosses the undervoltage protection threshold and the device shuts down. If hiccup mode is selected, then after a hiccup delay time (8.96 ms + 7× programmed soft-start time), the controller restarts. If the overcurrent condition remains, the procedure is repeated and the device enters hiccup mode. During the CCM, the negative current limit (NCL) protects the external FET from carrying too much current. The OCLN detect threshold is set at the same absolute value as positive current limit (OCLP) but with negative polarity. Note that the threshold still represents the valley value of the inductor current. When an OCLP or OCLN event occurs, the corresponding fault signals (IOUT_OC and IOUT) of the STATUS_WORD register is latched to indicate the faults and can be read via PMBus.