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DC-to-DC converter capable of preventing overvoltages
| Details |
Inventors: Saeki, Mitsuo; Yano, Hidetoshi; Ozawa, Hidekiyo;
Assignee: Fujitsu Limited (Kawasaki, JP)
Primary Examiner: Sherry; Michael J.
Assistant Examiner:
Attorney, Agent or Firm: Staas & Halsey LLP
To avoid burning out a capacitor in a synchronous rectification type DC-to-DC converter due to overvoltages, the synchronous rectification type DC-to-DC converter includes a storage unit storing therein power derived from a power supply, switching elements connecting and disconnecting respective signal paths from power and ground, and a control unit controlling the connecting/disconnecting operations of the switching elements to maintain a voltage output from the storage unit at a predetermined value. The DC/DC converter also includes an overvoltage detecting unit monitoring a voltage derived from the power supply to thereby output an alarm signal when the voltage derived from the power supply exceeds a preselected voltage value, a shortcircuiting unit influencing the connecting conditions of the switching elements when the alarm signal from the overvoltage detecting unit is input therein, whereby the voltage derived from the power supply is shortcircuited, and an interrupting unit interrupting one of the signal paths by the power shortcircuited by the shortcircuiting unit. |
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DETAILED DESCRIPTION The present invention has an object to provide a compact synchronous rectification mode voltage drop type DC/DC converter with a high converting efficiency.
Concretely speaking, this DC/DC converter can be constructed of a simple circuit arrangement, and can be protected from an overvoltage appearing in an input voltage thereto.
Also, this DC/DC converter can be protected from fire and smoke explosion of a capacitor caused by receiving overvoltages.
A DC/DC converter, according to the present invention, is such a synchronous rectification type DC-to-DC converter including: storage means for storing therein power derived from a power supply; a first switch element provided on a first signal path used to connect said power supply with said storage means, for connecting/disconnecting said first signal path; a second switch element provided on a second signal path used to connect said first switch element with said storage means, for connecting/disconnecting said second signal path to/from the ground; and control means for controlling the connecting/disconnecting operations of said first switch element and said second switch so as to maintain a voltage outputted from said storage means at a predetermined value.
A first IC/DC converter of the present invention is an apparatus capable of protecting a circuit (for instance, an organic capacitor) of the DC/DC converter when an input voltage becomes an overvoltage.
This first DC/DC converter is comprised of an overvoltage detecting means, a shortcircuiting means, and an interrupting means.
The overvoltage detecting means monitors a voltage derived from said power supply to thereby output an alarm signal when said voltage derived from said power supply exceeds a preselected voltage value.
This alarm signal is inputted to the shortcircuiting means.
The shortcircuiting means brings said first switch element and said second switch element to connecting conditions when the alarm signal from the overvoltage detecting means is inputted thereinto, whereby the voltage derived from said power supply is shortcircuited
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Metal Working 
