SLUSBP5E March   2014  – July 2018 TPS92601-Q1 , TPS92602-Q1

UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1. 3.1 Typical Schematic
  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 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 Fixed-Frequency PWM Control
      2. 7.3.2 Slope-Compensation Output Current
      3. 7.3.3 Boost-Current Limit
      4. 7.3.4 Oscillator and PLL
      5. 7.3.5 Control Loop Compensation
      6. 7.3.6 LED Open-Circuit Detection
      7. 7.3.7 Output Short-Circuit and Overcurrent Detection
      8. 7.3.8 Measuring LED Current During a Non-Failure Condition
      9. 7.3.9 LED Dimming Options
        1. 7.3.9.1 Analog Dimming
        2. 7.3.9.2 PWM Dimming
    4. 7.4 Device Functional Modes
      1. 7.4.1 Undervoltage and Overvoltage Shutdown
      2. 7.4.2 Overtemperature Shutdown
      3. 7.4.3 Device State Diagram
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Boost Regulator With Separate or Paralleled Channels
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1  Switching Frequency
          2. 8.2.1.2.2  Maximum Output-Current Set Point
          3. 8.2.1.2.3  Output Overvoltage-Protection Set Point
          4. 8.2.1.2.4  Duty Cycle Estimation
          5. 8.2.1.2.5  Inductor Selection
          6. 8.2.1.2.6  Rectifier Diode Selection
          7. 8.2.1.2.7  Output Capacitor Selection
          8. 8.2.1.2.8  Input Capacitor Selection
          9. 8.2.1.2.9  Current Sense and Current Limit
          10. 8.2.1.2.10 Switching MOSFET Selection
          11. 8.2.1.2.11 Loop Compensation
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Boost-to-Battery Regulator
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1  Switching Frequency
          2. 8.2.2.2.2  Maximum Output-Current Set Point
          3. 8.2.2.2.3  Output Overvoltage-Protection Set Point
          4. 8.2.2.2.4  Duty Cycle Estimation
          5. 8.2.2.2.5  Inductor Selection
          6. 8.2.2.2.6  Rectifier Diode Selection
          7. 8.2.2.2.7  Output Capacitor Selection
          8. 8.2.2.2.8  Input Capacitor Selection
          9. 8.2.2.2.9  Current Sense and Current Limit
          10. 8.2.2.2.10 Switching MOSFET Selection
          11. 8.2.2.2.11 Loop Compensation
        3. 8.2.2.3 TPS92602y-Q1 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 Related Links
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

7.3.4 Oscillator and PLL

The switching frequency is adjustable over a range from 100 kHz to 600 kHz by placing a resistor on the RT pin. The RT pin voltage is typically 0.5 V and must have a resistor to ground to set the switching frequency. To determine the timing resistance for a given switching frequency, use Equation 2 or the curve in Figure 3. To reduce the solution size one would typically set the switching frequency as high as possible, but give consideration to tradeoffs of the supply efficiency, maximum input voltage, and minimum controllable on-time.

Equation 2. TPS92601-Q1 TPS92602-Q1 eq03_RRT_SLUSBP5.gif

One can also use the RT pin to synchronize the controllers to an external system clock, over a range from 100 kHz to 600 kHz. Apply a square wave to the RT pin to use this synchronization feature. The square wave must transition lower than 0.8 V and higher than 2 V on the RT pin and have an on-time greater than 70 ns and an off time greater than 70 ns. The synchronization frequency range is 100 kHz to 600 kHz. The rising edge of GDRV1 is synchronized to the falling edge of the RT pin signal.

Leaving the RT pin open or shorted to ground with no external system clock signal is present disables both boost controllers, and both PWM dimming FETs switch off. In order to recover from this global failure state, (for example, after the failure condition on the RT pin has been removed) there must be one global disable-and-enable cycle (active shutdown by pulling both PWMINx pins low for t > t(CH_OFF), and setting one or both PWMINx pins high for t > t(CH_ON)).