The majority of switched mode AC-DC and DC-DC power supplies/converters use analogue techniques to regulate/control the output voltage, current, and power factor correction circuits, etc. The closest that most of these devices come to looking a bit digital (On/Off states) in nature is by employing Pulse Width Modulation (PWM) in their switching regulator circuits; but even that is a bit of a stretch.
In recent years, new integrated circuits (ICs) have been developed that can replace “analogue” control ICs and discrete circuits, which are used extensively in all power devices, with those that are, at least in part, “digital” in nature. These internal ICs and circuits perform such control functions as: voltage regulation (VR), power factor correction (PFC), pulse width modulation (PWM) control, internal monitoring/alarms, and external communications.
The advantage of these digital ICs is that they can be programmed by engineers with digital or analogue electronics training. And, since the Universities are pumping out more digital (e.g., computer science) than analogue engineers these days, these digital ICs are becoming attractive. However, at present the cost of these digital ICs (along with NRE for the equipment needed to program the devices) is still higher than for the mature analogue ICs. Nonetheless, some predict that these IC costs will become equal within the next 12 months or so. A potential disadvantage of these digital ICs is that, by their nature, they require a high speed clock to operate, which can add to the radiated and conducted noise coming from the power supply or converter. However, advanced functions such as fault diagnostics/prevention and improved power efficiencies are among the promises of the new digital control ICs.