SLVAFA9 March   2022 TPS82130 , TPSM82903

 

  1.   Trademarks
  2. 1Introduction
  3. 2Power Density
  4. 3Achieving a Smaller Solution
    1. 3.1 Fewer External Components
    2. 3.2 Smart Configuration Pin
    3. 3.3 VSET
  5. 4Reducing Power Loss
    1. 4.1 Junction Temperature
    2. 4.2 Automatic Efficiency Enhancement (AEE™)
    3. 4.3 Switching Frequencies and FET RDS(ON)
    4. 4.4 Auto PFM/PWM vs. Forced PWM
  6. 5Application Flexibility
    1. 5.1 Quiescent Current
    2. 5.2 Lower and More Accurate Output Voltages
    3. 5.3 Capacitive Discharge
  7. 6Summary
  8. 7References

4.3 Switching Frequencies and FET RDS(ON)

The TPSM8290x switching frequency can be set to 1 MHz or 2.5 MHz using the smart configuration pin. This is useful to provide the user the flexibly to set the switching frequency that fits the applications. To improve the efficiency and reduce switching losses of the converter, 1 MHz can be selected, with condition VOUT has to be less or equal to 2.0 V. This selection is ideal for most applications that have efficiency or thermals are the main concern. For applications VOUT>2.0 V, 2.5 MHz is required.

The Figure 4-1 compares the efficiency of the two devices and that translates to thermal performance as shown in Figure 4-2 and Figure 4-3. The improved efficiency at heavy load is mainly coming from the improved RDS(ON) of the High side FET and Low side FET. The TPS82130 has double RDS(ON) of 120 mΩ/50 mΩ vs 62 mΩ/22 mΩ of the TPSM82903.



Figure 4-1 Efficiency Curves of TPSM82903 vs. TPS82130, VIN=12 V, VO=1.2 V in Auto PFM/PWM mode.


Figure 4-2 Thermal Performance of TPSM82903EVM, VIN=12 V, VO=1.2 V, 3 A.


Figure 4-3 Thermal Performance of TPS82130EVM, VIN=12 V, VO=1.2 V, 3 A.

The thermal images shown in Figure 4-2 and Figure 4-3 were taken using FLIR thermal camera. The emissivity of the camera is set 0.94. The distance from the camera to the board is 5 inches. The measurements are taken without any airflow or controlled air. Room temperature is ~25°C.