Bode Plot Analysis

Last modified by Microchip on 2025/02/03 13:39

Bode Plot vs. RINJ

Bode Plot vs. RINJ

Here we show only lab testing of the control loop with a Bode100 analyzer. The MPLAB® Mindi™ Analog Simulator simulations do not correlate well with the lab testing. Some similarities, but not great.

  1. Constant On-Time (COT) and Adaptive Constant On-Time (ACOT) control is not compensated by the traditional means of placing poles and zeroes with type-2 or type-3 compensation.
  2. Note that the Bode100 results show very little increase in bandwidth (Fco frequency) and also maintain excellent phase margin. This is in contrast to the transient response performance.

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Bode Plot vs. CFF

Bode Plot vs. CFF

Here we show only lab testing of the control loop with a Bode100 analyzer. This is because the MPLAB Mindi simulations do not correlate well with the lab testing.

  1. COT and ACOT control is not compensated by the traditional means of placing poles and zeroes with type-2 or type-3 compensation.

  2. Note that the Bode100 results show a decrease in bandwidth (Fco frequency). This is in major contrast to the transient response performance.

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Summary

  • Microchip’s ACOT control enables high-performance buck controllers, regulators, and modules
  • ACOT loop optimization is non-traditional
    • Compensation is not required
      • Classic type-2 and type-3 compensation is not employed
    • Ripple injection is needed for most high-performance designs, and this is what compensates for and optimizes the loop and transient performance
  • MPLAB Mindi Analog Simulator simulations are a good tool for beginning the design process
    • Like all designs, verification of the design in hardware is recommended

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