Power circuit and method for controlling same

A power circuit for feeding a load current to a load in which said load current repeats periodically and alternately a burst flow in a burst period and a non-burst flow in a non-burst period comprising:

• a power source section made up of a direct current power source whose one terminal is connected to a negative polarity;
• a source power controlling section, to control a current fed from said power source section being connected to an input terminal and to feed said current to a load being connected to an output terminal;
• an energy storing section having a storage capacitor being connected between said output terminal and a negative polarity;
• and
• wherein said source power controlling section is provided with a current controlling circuit to control a resistance value of a detecting resistor whose one terminal is connected to said negative polarity according to a result of detection of a voltage input from said power source section and a switching circuit which has a step-up DC-DC (direct current to direct current) converter circuit made up of a voltage detecting circuit to detect a voltage of an output terminal, a coil and diode being connected in series between an input terminal and an output terminal, a capacitor being connected between said output terminal and a negative polarity and a switching device being connected between a connecting point between said coil and said diode and another terminal of said detecting resistor andwhich controls a flowing period of an output current by exerting control on said switching device according to a control signal being produced by a signal having detected a change in a current of said switching device using a voltage value at said other terminal of said detecting resistor and by a signal having detected a voltage at said output terminal.

A power circuit for feeding a load current to a load in which said load current repeats periodically and alternately a burst flow in a burst period and a non-burst flow in a non-burst period comprising:

• a power source section made up of a direct current power source whose one terminal is connected to a negative polarity;
• a source power controlling section to control a current fed from said power source section being connected to an input terminal and to feed said current to a load being connected to an output terminal;
• an energy storing section having a storage capacitor being connected between said output terminal and a negative polarity;
• and
• wherein said source power controlling section is provided with a current controlling circuit to control a resistance value of a detecting resistor whose one terminal is connected to an input terminal according to a result of detection of a voltage input from said power source section and a switching circuit which has a step-down DC-DC converter circuit made up of a voltage detecting circuit to detect a voltage of an output terminal, a switching device and a coil being connected in series between another terminal of said detecting resistor and an output terminal, a capacitor being connected between the output terminal and said negative polarity and a diode being connected between said negative polarity and a connecting point between said switching device and said coil, and which controls a flowing period of an output current by exerting control on said switching device according to a control signal being produced by a signal having detected a change in an input current based on a voltage across said detecting resistor and by a signal having detected a voltage at said output terminal.

A method for controlling apower circuit to feed a load current to a load in which said load current repeats periodically and alternately a burst flow in a burst period and a non-burst flow in a non-burst period which has a power source section made up of a direct current power source whose one terminal is connected to a negative polarity, a source power controlling section to control a current fed from said power source section being connected to an input terminal and to feed said current to a load being connected to an output terminal, and an energy storing section having a storage capacitor being connected between said output terminal and a negative polarity, said method comprising:

• a step of controlling a resistance value of a detecting resistor whose one terminal is connected to said negative polarity according to a result of detection of a voltage input from said power source section;
• and
• a step of controlling a flowing period of an output current by exerting control on said switching device according to a control signal being produced by a signal having detected a change in a current of said switching device using a voltage value at another terminal of said detecting resistor and by a signal having detected a voltage at said output terminal in a step-up DC-DC converter circuit made up of a coil and diode being connected in series between an input terminal and an output terminal, a capacitor being connected between said output terminal and a negative polarity and a switching device being connected between a connecting point between said coil and said diode and said other terminal of said detecting resistor.

A method for controlling a power circuit to feed a load current to a load in which said load current repeats periodically and alternately a burst flow in a burst period and a non-burst flow in a non-burst period which has a power source section made up of a direct current power source whose one terminal is connected to a negative polarity, a source power controlling section to control acurrent fed fromsaidpower source section being connected to an input terminal and to feed said current to a load being connected to an output terminal, and an energy storing section having a storage capacitor being connected between said output terminal and said negative polarity, said method comprising:

• a step of controlling a resistance value of a detecting resistor whose one terminal is connected to an input terminal according to a result of detection of a voltage input from said power source section;
• and
• a step of controlling a flowing period of an output current by exerting control on said switching device according to a control signal being produced by a signal having detected a change in an input current based on a voltage across said detecting resistor and by a signal having detected a voltage at said output terminal in a step-down DC-DC converter circuit made up of a switching device and a coil being connected in series between another terminal of said detecting resistor and an output terminal, a capacitor being connected between the output terminal and said negative polarity, and a diode being connected between a connecting point between said switching device and said coil and said negative polarity.