SLVS927F March   2009  – July 2018 TPS65023-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
    1.     Pin 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
    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 Step-Down Converters, VDCDC1, VDCDC2, and VDCDC3
      2. 8.3.2 Soft Start
      3. 8.3.3 Active Discharge When Disabled
      4. 8.3.4 Power-Good Monitoring
      5. 8.3.5 Low-Dropout Voltage Regulators
      6. 8.3.6 Undervoltage Lockout
    4. 8.4 Device Functional Modes
      1. 8.4.1 VRTC Output and Operation With or Without Backup Battery
      2. 8.4.2 Power-Save Mode Operation (PSM)
      3. 8.4.3 Low-Ripple Mode
      4. 8.4.4 100% Duty-Cycle Low-Dropout Operation
      5. 8.4.5 System Reset and Control Signals
        1. 8.4.5.1 DEFLDO1 and DEFLDO2
        2. 8.4.5.2 Interrupt Management and the INT Pin
    5. 8.5 Programming
      1. 8.5.1 Power-Up Sequencing
      2. 8.5.2 Serial Interface
    6. 8.6 Register Maps
      1. 8.6.1 VERSION Register (address: 00h) Read-Only
      2. 8.6.2 PGOODZ Register (address: 01h) Read-Only
        1. Table 5. PGOODZ Register Field Descriptions
      3. 8.6.3 MASK Register (address: 02h)
      4. 8.6.4 REG_CTRL Register (address: 03h)
        1. Table 6. REG_CTRL Register Field Descriptions
      5. 8.6.5 CON_CTRL Register (address: 04h)
        1. Table 7. CON_CTRL Register Field Descriptions
      6. 8.6.6 CON_CTRL2 Register (address: 05h)
        1. Table 8. CON_CTRL2 Register Field Descriptions
      7. 8.6.7 DEFCORE Register (address: 06h)
        1. Table 9. DEFCORE Register Field Descriptions
      8. 8.6.8 DEFSLEW Register (address: 07h)
        1. Table 10. DEFSLEW Register Field Descriptions
      9. 8.6.9 LDO_CTRL Register (address: 08h)
        1. Table 11. LDO_CTRL Register Field Descriptions
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Reset Condition of DCDC1
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Inductor Selection for the DC-DC Converters
        2. 9.2.2.2 Output Capacitor Selection
        3. 9.2.2.3 Input Capacitor Selection
        4. 9.2.2.4 Output Voltage Selection
        5. 9.2.2.5 VRTC Output
        6. 9.2.2.6 LDO1 and LDO2
        7. 9.2.2.7 TRESPWRON
        8. 9.2.2.8 VCC Filter
      3. 9.2.3 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 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.4.2 Power-Save Mode Operation (PSM)

As the load current decreases, the converters enter the power-save mode of operation. During PSM, the converters operate in a burst mode (PFM mode) with a frequency between 750 kHz and 2.25 MHz, nominal, for one burst cycle. However, the frequency between different burst cycles depends on the actual load current and is typically far less than the switching frequency, with a minimum quiescent current to maintain high efficiency.

To optimize the converter efficiency at light load, the average current is monitored, and if in PWM mode the inductor current remains below a certain threshold, then PSM is entered. The typical threshold to enter PSM is calculated as follows:

Equation 1. TPS65023-Q1 q1_ipfmdcdc_lvs927.gif

During PSM, the output voltage is monitored with a comparator, and by maximum skip burst duration. As the output voltage falls below the threshold, set to the nominal VO, the P-channel switch turns on, and the converter effectively delivers a constant current defined as follows.

Equation 2. TPS65023-Q1 q2_ipfm2_lvs927.gif

If the load is below the delivered current, then the output voltage rises until the same threshold is crossed in the other direction. All switching activity ceases, reducing the quiescent current to a minimum until the output voltage has again dropped below the threshold. The power-save mode is exited, and the converter returns to PWM mode if either of the following conditions is met:

  • the output voltage drops 2% below the nominal VO due to increasing load current
  • the PFM burst time exceeds 16 × 1 / fS (7.11 μs typical).

These control methods reduce the quiescent current to typically 14 μA per converter, and the switching activity to a minimum, thus achieving the highest converter efficiency. Setting the comparator thresholds at the nominal output voltage at light load current results in a low output-voltage ripple. The ripple depends on the comparator delay and the size of the output capacitor. Increasing capacitor values makes the output ripple tend to zero. The PSM is disabled through the I2C interface to force the individual converters to stay in fixed-frequency PWM mode.