SLVAFH3 December   2022 TPS6213013A-Q1 , TPS62130A-Q1 , TPS62133A-Q1 , TPS62150A-Q1 , TPS62152A-Q1 , TPS62153A-Q1 , TPS62901-Q1 , TPS62902-Q1 , TPS62903-Q1 , TPS62992-Q1 , TPS62993-Q1

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction
  4. 2Achieving a Smaller Solution
    1. 2.1 Smaller Package and Fewer External Components
    2. 2.2 Smart Configuration Pin
    3. 2.3 VSET
  5. 3Reducing Power Loss
    1. 3.1 Junction Temperature
    2. 3.2 Automatic Efficiency Enhancement (AEE)
    3. 3.3 Quiescent Current
    4. 3.4 Auto PFM/PWM vs. Forced PWM
  6. 4Application Flexibility
    1. 4.1 1.0 MHz and 2.5 MHz Switching Frequencies
    2. 4.2 Lower and More Accurate Output Voltages
    3. 4.3 Output Voltage Discharge
    4. 4.4 Wettable Flanks
  7. 5Summary
  8. 6References

3.2 Automatic Efficiency Enhancement (AEE)

The AEE feature in the TPS629xx-Q1 provides highest efficiency over the entire input and output voltage range by automatically adjusting the converter's switching frequency when 2.5 MHz is selected. The efficiency decreases when VOUT decreases and or VIN increases. In order to keep the efficiency high over the entire duty cycle range (VOUT/VIN ratio), the switching frequency is adjusted by changing the ton of the converter as shown in Equation 1. This mode also maintains the current ripple to ensure the current limits of the device aren't exceeded at the maximum output current. Equation 2 shows how setting the calculated ton can keep the inductor current ripple constant and independent of VOUT.

Equation 1. t o n n s = 100 × V I N V I N - V O U T
Equation 2. ∆ I L m A = 0.1 × V I N V L μ H

The AEE feature provides an efficiency enhancement for various duty cycles, especially for lower Vout values, where fixed frequency converters suffer from a significant efficiency drop. Furthermore, this feature compensates for the very small duty cycles of high VIN to low VOUT conversion, which limits the control range in other topologies.