JP2016163381A - Dc power supply unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DC power supply unit that is efficient over a wide output voltage range by switching a combined inductance constituted of a plurality of inductors forming a switching regulator circuit according to load power.SOLUTION: A DC power supply unit includes a switching regulator circuit involving fluctuations in a switching frequency while controlling output power and switches connection of a plurality of inductors forming a switching regulator circuit so that a combined inductance decreases when output power increases and increases when the output voltage decreases.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a DC power supply device.

  In the switching regulator circuit, means for changing the duty at a constant frequency, means for changing the switching frequency, and the like are used to control the output power. Although there exists a switching regulator circuit like patent document 1 made to operate | move in a critical mode, in such an operation | movement, the fluctuation | variation of a switching frequency is accompanied by control of output electric power.

Japanese Patent Laid-Open No. 06-165508

  Like switching regulators that operate in critical mode, switching regulator circuits that involve fluctuations in the switching frequency for output power control require appropriate inductance settings according to the input / output conditions. For example, when the operation is performed under a load condition that deviates from the condition at the time of setting the inductance, the power supply efficiency may decrease due to an increase in switching frequency or an increase in inductor current.

  An object of the present invention is to provide a high-efficiency DC power supply device in a wide output power range by switching a combined inductance composed of a plurality of inductors constituting a switching regulator circuit in accordance with load power.

  The output power is reduced so that when the output power is increased, the combined inductance is reduced by connecting a plurality of inductors constituting the switching regulator circuit with a switching regulator circuit that involves switching of the switching frequency to control the output power. In some cases, switching is performed so that the combined inductance increases.

  According to the present invention, the connection of the plurality of inductors constituting the switching regulator circuit is switched so that the combined inductance decreases when the output power increases, and the combined inductance increases when the output power decreases, It is possible to optimize the switching frequency in a wide output power range and improve the power supply efficiency.

It is a figure which shows the structural example of one Example of this invention.

  An example of this embodiment will be described with reference to FIG.

  The DC power supply device 1 includes a switching regulator circuit 2 that operates in a critical mode. The switching regulator circuit 2 includes a main inductor 3, a sub inductor 4, a switch 6, an input capacitor 7, a switch 8, a diode 9, an output capacitor 10, and a switching determination unit 11. The combined inductance 5 is switched.

  When the output power of the switching regulator circuit 2 is operating below the threshold value determined as low power, the switching determination means 11 detects it and turns off the switch 6. By turning off the switch 6, the value of the combined inductance 5 depends only on the value of the main inductor 3, and becomes a larger value than when the switch 6 is on. By taking the combined inductance 5 as a large value, it is possible to suppress an increase in switching frequency when the output power is low and to reduce loss due to switching.

  When the output power of the switching regulator circuit 2 is operating above the threshold value determined as high power, the switching determination means 11 detects it and turns on the switch 6. By turning off the switch 6, the value of the combined inductance 5 becomes a value obtained by connecting the main inductor 3 and the sub-inductor 4 in parallel. Thereby, the increased inductor current can be shunted to the main inductor 3 and the sub-inductor 4, and the copper loss can be reduced.

  As described above, the connection of the plurality of inductors constituting the switching regulator circuit 2 is switched so that the combined inductance 5 decreases when the output power increases, and the combined inductance 5 increases when the output power decreases. Thus, it is possible to optimize the switching frequency in a wide output power range and improve the power supply efficiency.

DESCRIPTION OF SYMBOLS 1 DC power supply device 2 Switching regulator circuit 3 Main inductor 4 Sub inductor 5 Synthetic inductance 6 Switch 7 Input capacitor 8 Switch 9 Diode 10 Output capacitor 11 Switching judgment means

Claims (1)

It has a switching regulator circuit that accompanies fluctuations in the switching frequency to control the output power,
A DC power supply characterized in that the connection of a plurality of inductors constituting the switching regulator circuit is switched so that the combined inductance decreases when the output power increases, and the combined inductance increases when the output power decreases. .