Power-supply device

• US 20050127886A1
• Filed: 01/27/2005
• Published: 06/16/2005
• Est. Priority Date: 06/17/2002
• Status: Abandoned Application

• Current Assignee: Akihiko Kanouda, Katsunori Hayashi, Koji Tateno, Shinichi Yoshida, Takashi Sase
• Original Assignee: Akihiko Kanouda, Katsunori Hayashi, Koji Tateno, Shinichi Yoshida, Takashi Sase
• Inventors: Yoshida, Shinichi, Kanouda, Akihiko, Tateno, Koji, Sase, Takashi, Hayashi, Katsunori
• Application Number:
  US11/043,086
• Publication Number:
  US 20050127886A1
• Time in Patent Office: Days
• US Class Current: 323/282
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel
• CPC Class Codes: H02M 3/1588 comprising at least one synchronous rectifier element H02M3/1582, H02M3/1584 take precedence
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A step-down type DC-DC power supply device implements both the stabilization of the control loop and the responsibility at the same time. In the power-supply device, an output power signal is fed back to an error amplifier after having passed through a CR smoothing filter provided independently of a power LC smoothing filter. Also, independently of the duty controls over Power MOSFETs, i.e., upper-side/lower-side semiconductor switching components in the steady state, an output from the power LC smoothing filter is added to an upper and lower limit-mode-equipped control circuit, thereby, at the transient state, forcefully setting the duty α at either 0% or 100%.

Claims

1. A power-supply device including a step-down DC-DC converter, comprising:

power semiconductor switching components,

driving means for driving said power semiconductor switching components,

a pulse-width modulation oscillator to supply said driving means with a driving signal,

an error amplifier to supply said pulse-width modulation oscillator with an error signal indicating a comparison result between a reference value and an output power,

wherein a control loop of said power-supply device includes a filter provided independently of a power output filter through which said output power passes, an output signal corresponding to said output power being fed back to said error amplifier after having passed through said independently provided filter, and

wherein said power output filter is an LC filter comprised of an inductor and a capacitor, said independently provided filter being a CR filter comprised of a capacitor and a resistor, said CR filter being connected to both ends of said inductor of said power output filter, and said output signal being fed back to said error amplifier after having passed through said CR filter, and

a transient variation detecting circuit, said transient variation detecting circuit;

detecting said output power from an output terminal of said power output filter, and, if said output power has been found to exceed a predetermined upper-limit value, outputting a signal for setting the duty α

of said pulse-width modulation oscillator at 0%, and, if said output power has been found to be lower than a predetermined lower-limit value, outputting a signal for setting said duty α

of said pulse-width modulation oscillator at 100%.