Datasheet

13

002-37370 Rev. *B

2023-10-10

EZ-PD™ PAG2S-AC integrated USB PD and secondary-side ACF

controller

Functional description

3.3

Modes of operation - PWM and ACF

PAG2S-AC supports multiple modes of operation: CrCM, valley switching, DCM, CCM, and burst mode for light

load operations. Firmware allows configurability for minimum/maximum pulse width, period, and pulse skip or

burst levels. PAG2S-AC also supports Active Clamp Flyback control, where it sends an ACF signal for a short

duration before sending the PWM signal. PAG2P uses the ACF signal to drive the high-side gate driver and the PWM

signal to drive the low-side gate driver. ACF recycles the energy in the snubber capacitor, thereby improving

system efficiency. ACF pulse-width is firmware configurable, which enables optimization for each design.

Figure 6 and Figure 7 show the PWM and ACF functionality in DCM and CCM modes respectively.

Figure 6

PWM_ACF in DCM mode

Ramp

Error Amplifier Output

Time

Primary FET drain

voltage

PWM

Primary FET ON,

SR FET OFF

Primary FET OFF,

SR FET ON

ACF

Snubber voltage