Peak current mode (PCM) and internally compensated advanced current mode (ACM) are two commonly used control modes in TI fixed frequency buck regulators portfolio.

Fixed frequency control modes can provide better switching frequency accuracy, which can offer low EMI / noise via true fixed frequency, but at the cost of a slower transient response compared with D-CAP™ control mode with adaptive constant on time (COT) control method.

Peak current mode control with a fixed-frequency modulator requires Type II compensation circuitry to achieve acceptable bandwidth and phase margins for stability, increasing design complexity, size and cost.

Internally compensated advanced current mode (ACM) is a control topology proposed by TI based on PCM control scheme. It addresses a major challenge of PCM – especially in high frequency operation – is the minimum on time required to properly sense the current information to overcome large noise compared to the small sensed signal. Furthermore, it could achieve larger signal-to-noise ratio to achieve multi-megahertz switching frequency and could offer better load transient performance with internal compensation.