Electronic devices often need to generate multiple power regimes while only being powered by a single source. For example, a laptop computer may only have a single battery but may need to produce power regimes with different supply voltages for the various components on the laptop. Furthermore, regardless of the need for multiple power regimes, electronic devices often need to condition the power that is delivered to them from an external source. Returning to the example of a laptop, the laptop processor contains sensitive electronics and exhibits a widely varying power demand based on how hard the processor is working. Simply plugging in a DC version of the mains voltage source is not an option because the processor will not be shielded from dips or surges in the power supply and the power supply will likewise not be able to keep pace with the rapid transitions in the power drawn by the processor. The aforementioned requirements are addressed by power converters.
Power converters receive power from a supply power regime and generate a regulated power regime. In one example, the power converter stabilizes a supply voltage in the regulated power regime and provides a varying current from the supply power regime in order to do so. Varying the current allows such a power converter to supply the varying power needs of any components or devices in the regulated power regime while keeping the supply voltage of the regulated power regime stable. Other power converters generate the regulated power regime by varying the voltage while keeping the current stable or vary both the current and voltage to keep an amount of power delivered to the regulated regime stable.
Power converters that vary their conditions with the varying status of the load in the regulated regime need information regarding that status. A common way to provide this information is through an electrical feedback path from the load back to the converter. The system can be controlled by negative feedback that forces a parameter back to a controlled target by pushing in the opposite direction of a detected variance from that controlled target. However, the utilization of electrical feedback paths presents the possibility of instability. Both the phase shift and amplification of an electrical path can vary with frequency. As a result, a system that exhibits a negative feedback characteristic to signals of a given frequency may exhibit a positive feedback characteristic to signals of another frequency. Power converters can utilize compensators in their feedback system to ensure the overall system is stable and well-behaved.