SLUSBZ6A April   2016  – August 2016 TPS92515 , TPS92515-Q1 , TPS92515HV , TPS92515HV-Q1


  1. Features
  2. Applications
  3. Description
    1.     Simplified Buck LED Driver Application
  4. Revision History
  5. Device Comparison Table
  6. Pin Configuration and Functions
    1. Table 1. Pin Functions
  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 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  General Operation
      2. 8.3.2  Current Sense Comparator
      3. 8.3.3  OFF Timer
      4. 8.3.4  OFF-Timer, Shunt FET Dimming or Shunted Output Condition
      5. 8.3.5  Internal N-channel MOSFET
        1. Drop-Out
      6. 8.3.6  VCC Internal Regulator and Undervoltage Lockout (UVLO)
      7. 8.3.7  Analog Adjust Input
        1. IADJ Pin Clamp
        2. IADJ Pin Clamp Characteristic
        3. Analog Adjust (IADJ Pin) Control Methods
        4. IADJ Control Method Notes
      8. 8.3.8  Thermal Protection
        1. Maximum Output Current and Junction Temperature
      9. 8.3.9  Junction Temperature Relative Estimation
      10. 8.3.10 BOOT and BOOT UVLO
        1. Start-Up, BOOT-UVLO and Pre-Charged Condition
      11. 8.3.11 PWM (UVLO and Enable)
        1. Using PWM for UVLO (Undervoltage Lockout) Protection
          1. UVLO Programming Resistors
        2. Using PWM for Digitally Controlled Enable
        3. UVLO: VIN, VCC and BOOT UVLO
        4. Analog and PWM Dimming - Normalized Results and Comparison
    4. 8.4 Device Functional Modes
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 General Design Procedure
        1. Calculating Duty Cycle
        2. Calculate OFF-Time Estimate
        3. Calculate OFF-Time Resistor ROFF
        4. Calculate the Minimum Inductance Value
        5. Calculate the Sense Resistance
        6. Calculate Input Capacitance
        7. Calculate Output Capacitance
      2. 9.2.2 Design Requirements
      3. 9.2.3 Detailed Design Procedure
        1. Calculating Duty Cycle
        2. Calculate OFF-Time Estimate
        3. Calculate OFF-Time Resistor ROFF
        4. Calculate the Inductance Value
        5. Calculate the Sense Resistance
        6. Calculate Input Capacitance
        7. Verify Peak Current for Inductor Selection
        8. Calculate Output Capacitance
        9. Calculate UVLO Resistance Values
      4. 9.2.4 Application Curves
    3. 9.3 Dos and Don'ts
  10. 10Power Supply Recommendations
    1. 10.1 Input Source Direct from Battery
    2. 10.2 Input Source from a Boost Stage
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
        1. Related Links
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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


The TPS92515 is an internal N-channel MOSFET (monolithic NFET) hysteric control, buck regulator. Hysteretic operation allows a high control bandwidth and is ideal for shunt FET and LED matrix applications (series LED switched network). The high-side differential current sense with low adjustable threshold voltage via a 10:1 divider, provides an excellent method for regulating output current while maintaining high system efficiency. The device uses a controlled OFF-time (COFT) architecture to allow the converter to operate in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) with no external control loop compensation, and provides an inherent cycle-by-cycle current limit.

The adjustable current sense threshold provides the capability for analog dimming the LED current over the full range and the PWM dimming input allows for high-frequency PWM dimming control requiring no external components. Configuration options allow for easy implementation of external shunt FET dimming. See also the OFF-Timer, Shunt FET Dimming or Shunted Output Condition section.

The device does not internally limit the maximum attainable average LED current. It does have a thermal limit based on the maximum junction temperature. The maximum junction temperature is a function of the system operating points (efficiency, ambient temperature, thermal management), component choices, and switching frequency. This functionality allows the device to provide constant currents up to 1 A in a wide variety of applications and up to 2 A in a smaller sub-set of applications. This simple regulator contains all the features necessary to implement a high-efficiency, versatile, high-performance LED driver.