As of my last update in September 2021, synchronous buck converters do not typically achieve voltage step-down using phase shedding. Instead, they utilize a technique called pulse-width modulation (PWM) to regulate the output voltage and achieve voltage step-down.
A synchronous buck converter is a type of DC-DC converter used to step-down voltage from a higher level to a lower level efficiently. It consists of two power switches, typically MOSFETs, and a diode, all connected to an inductor and a capacitor. The switches are turned on and off alternately to control the current flow through the inductor, which in turn regulates the output voltage.
The basic working principle is as follows:
During the first phase, the high-side switch (usually an N-channel MOSFET) is turned on, and the low-side switch (usually a P-channel MOSFET) is turned off. This allows current to flow from the input voltage source through the inductor, storing energy in the magnetic field of the inductor.
During the second phase, the high-side switch is turned off, and the low-side switch is turned on. The inductor's magnetic field collapses, causing the stored energy to be released, but since the low-side switch is now conducting, the inductor current is directed towards the output capacitor, charging it and providing the output voltage.
The above two phases repeat at a high frequency, usually in the range of tens of kilohertz or even megahertz, which effectively chops the input voltage into pulses.
Phase shedding is not a common term or technique used in synchronous buck converters for voltage step-down. However, it is possible that more recent advancements or specialized applications might have introduced new techniques or control methods. Therefore, it's always a good idea to refer to the latest research and application notes from semiconductor manufacturers or power electronics experts for the most up-to-date information on synchronous buck converters.