SNVAAA6 September   2024 LM61495

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1OLED Driving Scheme
  5. 2Inverting Buck-Boost Concept
  6. 3PMP23333 Introduction
    1. 3.1 PMP23333 Schematic
  7. 4Design Considerations
    1. 4.1 VIN, VOUT Range
    2. 4.2 Inductor Selection and Maximum Output Current
    3. 4.3 Capacitor Selection
    4. 4.4 Efficiency and Thermal Considerations
    5. 4.5 Optional Enable (EN) Level Shifter
  8. 5Summary
  9. 6References

3 PMP23333 Introduction

This application note uses TI’s reference design PMP23333. PMP23333 design used LM61495 synchronous buck regulator, with internal top and bottom FETs, which is configured as a synchronous inverting buck-boost converter. The LM61495 is regulator that provide either fixed or adjustable output voltage that can be set from 1V to 95% of expected input voltage. LM61495 can operate under a wide input voltage range from 3V to 36V and have transient tolerance up to 42V which can give proper design flexibility to designers.

PMP23333 (Top) Board ImageFigure 3-1 PMP23333 (Top) Board Image
PMP23333 (Bottom) Board ImageFigure 3-2 PMP23333 (Bottom) Board Image
Table 3-1 Voltage and Current Requirements of PMP23333
ParameterSpecifications
VIN12 VDC ±10%
VOUT–8 VDC
IOUT2.7A continuous (4A peak)
FSW400kHz nominal

This design generates an output of –8V, capable of delivering 2.7A continuous (4A peak) of current to the load, from a +12V, ±10% input. The design covers up to 32W power rating. So PMP23333 can be a great start point of design to cover up to 49 inch OLED panel for monitor, small TV applications. As described in Section 1, -VOUT can be decided by OLED characteristics. -V­OUT value can be set by configuration of feedback resistors as shown in Figure 3-3, PMP23333 schematic. If designer requires higher power rating for bigger OLED panel, controller design needs to be considered due to current, thermal limitations, and so on.