The external PWM Reset mode can be used in power factor correction applications.
In the example below, the external trigger input is the PWMEXTRG1 (therefore the PWM channel used for regulation is the channel 1). The PWM channel 1 period (CPRD in the PWM Channel Period Register of the channel 1) must be programmed so that the TRGIN1 event always triggers before the PWM channel 1 period elapses.
In the figure below, an external circuit (not shown) is required to sense the inductor current IL. The internal PWM counter of the channel 1 is cleared when the inductor current falls below a specific threshold (IREF). This starts a new PWM period and increases the inductor current.
Figure 1. External PWM Reset Mode: Power Factor Correction
Application
