ZHCSDQ0C March 2015 – August 2018 LP8758-B0
PRODUCTION DATA.
Under heavy load conditions, the 4-phase converter switches each channel 90° apart. As a result, the 4-phase converter has an effective ripple frequency four times greater than the switching frequency of any one phase. However, the parallel operation decreases the efficiency at light load conditions. In order to overcome this operational inefficiency, the LP8758 can change the number of active phases to optimize efficiency for the variations of the load. This is called phase adding/shedding. The concept is illustrated below in Figure 9.
The converter can be forced to multi-phase operation by the BUCK0_CTRL1.BUCK0_FPWM_MP bit. If the regulator operates in forced multi-phase mode the forced PWM operation is automatically used. If the multi-phase operation is not forced, the number of phases are added and shedded automatically to follow the required output current.