Multi-mode power supply circuit with a normal operational mode and a pass-through operational mode and a method for operating the multi-mode power supply circuit

摘要

A power supply circuit and a method for operating a power supply circuit involves selecting a normal operational mode or a pass-through operational mode for a switched mode power supply, in the normal operational mode, converting an input voltage of a power supply circuit to an intermediate voltage using a switching regulator of the switched mode power supply, in the pass-through operational mode, disabling the switching regulator such that the input voltage of the power supply circuit is unchanged by the switching regulator and an electric current consumption of the switching regulator approaches zero, and converting the intermediate voltage or the input voltage of the power supply circuit to an output voltage using a linear voltage regulator.

主权项

1. A method for operating a power supply circuit, the method comprising:
selecting a normal operational mode or a pass-through operational mode for a switched mode power supply; in the normal operational mode, converting an input voltage of the power supply circuit to an intermediate voltage using a switching regulator of the switched mode power supply, wherein the normal operational mode is a boost operational mode in which the intermediate voltage is higher than the input voltage of the power supply circuit or a buck operational mode in which the intermediate voltage is lower than the input voltage of the power supply, wherein in the normal operational mode, converting the input voltage of the power supply circuit to the intermediate voltage comprises monitoring the input voltage and selecting between the buck operational mode and the boost operational mode depending on a relationship between the input voltage and a desired output voltage level; in the pass-through operational mode, disabling the switching regulator using an internal bypass circuit within the switching regulator such that the input voltage of the power supply circuit is unchanged by the switching regulator and an electric current consumption of the switching regulator approaches zero; and converting the intermediate voltage or the input voltage of the power supply circuit to an output voltage using a linear voltage regulator, wherein the selecting the normal operational mode or the pass-through operational mode is performed based on an output current demand, wherein the pass-through operational mode is selected when the current demand is substantially zero.