SLYT837 January   2023 TPS543B22 , TPS548A28 , TPS56121

 

  1. 1 Introduction
  2. 2 Selecting and bounding the application
  3. 3 Designing the second-stage filter
  4. 4 Voltage-mode control architecture
  5. 5 D-CAP3 control architecture
  6. 6 Advanced current mode (ACM) control architecture
  7. 7 Efficiency penalty
  8. 8 Conclusion
  9. 9 References
  10. 10Related Websites

8 Conclusion

A second-stage filter is an easy, small, efficient and low-cost solution to design and provide low output voltage ripple for high current loads. There is no perfect control mode for every design situation, but a second-stage filter can be implemented in many buck converter control architectures. If you are designing with a network interface card SoC or a remote radio unit using an AFE, a second-stage filter will provide much lower ripple than a standard buck converter. Table 8-1 summarizes the ripple and the efficiency and size trade-offs associated with each device.

Table 8-1 Ripple, size and efficiency trade-offs.
Device Current Capability (A) Control Architecture Ripple Voltage (mV) Filter Size Power Loss penalty (W)
TPS543B22 20 ACM 1.3 92mm2 0.020
TPS548A28 15 D-CAP3 2.3 92mm2 0.021
TPS56121 15 Voltage Mode 1.9 92mm2 0.028