SLYY205A March   2021  – October 2022 TPS562211 , TPS562212 , TPS562231 , TPS563211 , TPS563212 , TPS563231 , TPS56339

 

  1.   At a glance
  2.   Authors
  3.   What is AECM control?
  4.   PCM
  5.   D-CAP2 control scheme
  6.   AECM control benefits
  7.   How AECM control works
  8.   PWM operation mode
  9.   PFM operation mode
  10.   Smart loop-bandwidth control
  11.   Conclusion
  12.   References
  13.   Additional Resources

PWM operation mode

The PWM mode control scheme is similar to PCM control. As shown in Figure 10, the internal clock initials one on-pulse; the high-side FET then turns on, with current increasing in the inductor. When the emulated ramp voltage, feedback voltage and slope compensation voltage reach the integrated reference voltage, the high-side FET turns off and the low-side FET turns on until the next clock cycle. Therefore, in PWM mode, the switching frequency is truly fixed.

GUID-20220324-SS0I-PT3Z-CSZK-XBVWMKCBVNQQ-low.gif Figure 9 AECM control block diagram.
Figure 10 AECM control scheme waveform: PWM operation mode (a); PFM operation mode (b).

Figure 11 shows the load-transient behavior of the AECM device. The duty cycle increases or decreases with a decrease or increase of VOUT.