SNVAA61 February   2023 LM5168 , LM5168-Q1 , LM5169 , LM5169-Q1

 

  1.   Inverting Buck-Boost Application for LM5168
  2.   Trademarks
  3. 1Inverting Buck-Boost Topology
    1. 1.1 Concept
    2. 1.2 Output Current Calculations
    3. 1.3 Voltage Range of Inverting Buck-Boost Configuration
  4. 2Design Considerations
    1. 2.1 Bypass Capacitor and Optional Schottky Diode
  5. 3External Components
    1. 3.1 Capacitor Selection
    2. 3.2 Inductor Selection
  6. 4Digital Pin Configurations
    1. 4.1 Optional Enable (EN) Level Shifter
    2. 4.2 Power-Good (PG) Pin
  7. 5Typical Performance
    1. 5.1 VOUT = -12 V Typical Performance
    2. 5.2 VOUT = -24 V Typical Performance
    3. 5.3 VOUT = -48 V Typical Performance
  8. 6Conclusion
  9. 7References

1 Inverting Buck-Boost Application for LM5168

The LM5168 is a synchronous buck converter with a wide input voltage range from 6 V to 115 V and maximum output current of 300 mA. The LM5168 can be configured as an inverting buck-boost (IBB) converter with a negative output voltage. This application note demonstrates how the LM5168 can be used as an inverting buck-boost converter, along with optional design considerations for inverting buck-boost converters such as a PGOOD or EN level-shifter. If higher output current is required, the LM5168 is pin-to-pin compatible with the 600-mA rated LM5169. Automotive grade versions, the LM5168-Q1 and LM5169-Q1, are also available.