US 7,071,668 B2Granted

Power circuit and method for controlling same

AssigneeNEC Tokin Corporation

InventorHiroshi Sasaki

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Abstract

A power circuit is provided which has a small current peak value from a power source even when a load current repeats periodically, and a burst flow in a burst period and a non-burst flow in a non-burst period alternates. The power circuit includes a power source section, a power controlling section, and an energy storing section having a storage capacitor being connected to an output terminal, a current controlling circuit to control values of detecting a voltage input from a power source section and a control switching device having a field effect transistor switch and a circuit made up of a capacitor in which a flowing period of an output current is controlled by exerting the field effect transistor switch according to a control signal being produced by detecting a change in an input power voltage using a voltage occurring at another terminal of the detecting resistor.

Claims24

Dependent claims

A power circuit for feeding a load current to a load in which said load current repeats periodically and alternates 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 having one terminal connected to a negative polarity;
a source power controlling section to control a current fed from a second terminal of said power source section connected to an input terminal to limit voltage drop in said power source section and to feed said current to a load connected to an output terminal;
and
an energy storing section having a storage capacitor connected between said output terminal and a negative polarity;
wherein said source power controlling section is provided with a current controlling circuit to control a resistance value of a detecting resistor section, said detecting resistor section having one terminal 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 circuit part comprising a switching device connected between an input terminal and an output terminal of said source power controlling section and a capacitor connected between said output terminal of said source power controlling section and a negative polarity, and which controls a flowing period of an output current by exerting control on said switching device according to a control signal produced by detecting a change in an input power voltage using a voltage value occurring at another terminal of said detecting resistor;
and
wherein a circuit constant of said source power controlling section, electrostatic capacity and internal resistance of said storage capacitor are determined by following equations:
T1+T2≦Tload
where “T1+T2” denotes a flowing period (Sec) of a power current and “Tload” denotes a load period (Sec):
Vo/2≧IC×{Rc+(Tload×Don)/(C×100)}=Vo3
where “Vo” denotes a voltage (V) of said storage capacitor when there is no load current, “IC” denotes a current (A) of said storage capacitor, “Rc” denotes an internal resistance (Ω) of said storage capacitor, “Don” denotes a duty ratio (%) of a load, “C” denotes a capacity (F) of a storage capacitor, and “Vo3” denotes an amount of a voltage drop (V) of a storage capacitor voltage occurring during a burst period.

8 more elements

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 having one terminal connected to a negative polarity;
a source power controlling section to control a current fed from a second terminal of said power source section being connected to an input terminal to limit voltage drop in said power source section and to feed said current to a load connected to an output terminal;
and
an energy storing section having a storage capacitor connected between said output terminal and a negative polarity;
wherein said source power controlling section is provided with a current controlling circuit to control a resistance value of a detecting resistor section, said detecting resistor section having one terminal 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 comprising a voltage detecting circuit to detect a voltage of an output terminal, a coil and diode connected in series between an input terminal and an output terminal of said source power controlling section, a capacitor connected between said output terminal of said source power controlling section and a negative polarity, and a switching device connected between a connection point of said coil and said diode and another terminal of said detecting resistor section, and which controls a flowing period of an output current by exerting control on said switching device according to a control signal produced by detecting a change in a current through said switching device using a voltage value at said other terminal of said detecting resistor section and a voltage at said output terminal;
and
wherein a circuit constant of said source power controlling section, electrostatic capacity and internal resistance of said storage capacitor are determined by following equations:
T1+T2≦Tload
where “T1+T2” denotes a flowing period (Sec) of a power current and “Tload” denotes a load period (Sec):
Vo/2≧IC×{Rc+(Tload×Don)/(C×100)}=Vo3
where “Vo” denotes a voltage (V) of said storage capacitor when there is no load current, “IC” denotes a current (A) of said storage capacitor, “Rc” denotes an internal resistance (Ω) of said storage capacitor, “Don” denotes a duty ratio (%) of a load, “C” denotes a capacity (F) of a storage capacitor, and “Vo3” denotes an amount of a voltage drop (V) of a storage capacitor voltage occurring during a burst period.

8 more elements

a power source section made up of a direct current power source-having one terminal connected to a negative polarity;
a source power controlling section to control a current fed from a second terminal of said power source section connected to an input terminal to limit voltage drop in said power source section and to feed said current to a load connected to an output terminal;
an energy storing section having a storage capacitor 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 section, said detecting resistor section having one terminal connected to an input terminal of said source power controlling section, 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 comprising a voltage detecting circuit for detecting a voltage of an output terminal, a switching device and a coil connected in series between another terminal of said detecting resistor section and an output terminal, a capacitor connected between the output terminal and said negative polarity, and a diode connected between said negative polarity and a connection 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 produced by detecting a change in an input current based on a voltage across said detecting resistor section, and a voltage at said output terminal;
and
wherein a circuit constant of said source power controlling section, electrostatic capacity and internal resistance of said storage capacitor are determined by following equations:
T1+T2≦Tload
where “T1+T2” denotes a flowing period (Sec) of a power current and “Tload” denotes a load period (Sec):
Vo/2≧IC ×{Rc+(Tload×Don)/(C×100)}=Vo3
where “Vo” denotes a voltage (V) of said storage capacitor when there is no load current, “IC” denotes a current (A) of said storage capacitor, “Rc” denotes an internal resistance (Ω) of said storage capacitor, “Don” denotes a duty ratio (%) of a load, “C” denotes a capacity (F) of a storage capacitor, and “Vo3” denotes an amount of a voltage drop (V) of a storage capacitor voltage occurring during a burst period.

8 more elements

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 with one terminal connected to a negative polarity, a source power controlling section to control a current fed from said power source section, connected to an input terminal, and to feed said current to a load connected to an output terminal, and an energy storing section having a storage capacitor connected between said output terminal and a negative polarity, said method comprising:

a step of controlling a resistance value of a detecting resistor section, said detecting resistor section having one terminal 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 a switching device in response to a control signal produced by detecting a change in an input power voltage using a voltage value occurring at another terminal of said detecting resistor section, wherein said switching device is connected between an input terminal and an output terminal and a capacitor is connected between said output terminal and a negative polarity;
and
wherein a circuit constant of said source power controlling section, electrostatic capacity and internal resistance of said storage capacitor are determined by following equations:
T1+T2≦Tload
where “T1+T2” denotes a flowing period (Sec) of a power current and “Tload” denotes a load period (Sec):
Vo/2≧IC×{Rc+(Tload×Don)/(C×100)}=Vo3
where “Vo” denotes a voltage (V) of said storage capacitor when there is no load current, “IC” denotes a current (A) of said storage capacitor, “Rc” denotes an internal resistance (Ω) of said storage capacitor, “Don” denotes a duty ratio (%) of a load, “C” denotes a capacity (F) of a storage capacitor, and “Vo3” denotes an amount of a voltage drop (V) of a storage capacitor voltage occurring during a burst period.

6 more elements

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 having one terminal connected to a negative polarity, a source power controlling section to control a current fed from said power source section and connected to an input terminal of said source power controlling section, and to feed said current to a load connected to an output terminal of said source power controlling section, and an energy storing section having a storage capacitor connected between said output terminal and a negative polarity, said method comprising:

a step of controlling a resistance value of a detecting resistor section having one terminal 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 a switching device according to a control signal produced by detecting a change in a current of said switching device using a voltage value at another terminal of said detecting resistor section, and a voltage at said output terminal in a step-up DC—DC converter circuit comprising a coil and diode connected in series between an input terminal and an output terminal, a capacitor connected between said output terminal and a negative polarity, and a switching device connected between a connection point of said coil and said diode and said other terminal of said detecting resistor section;
and
wherein a circuit constant of said source power controlling section, electrostatic capacity and internal resistance of said storage capacitor are determined by following equations:
T1+T2≦Tload
where “T1+T2” denotes a flowing period (Sec) of a power current and “Tload” denotes a load period (Sec):
Vo/2≧IC×{Rc+(Tload×Don)/(C×100)}=Vo3
where “Vo” denotes a voltage (V) of said storage capacitor when there is no load current, “IC” denotes a current (A) of said storage capacitor, “Rc” denotes an internal resistance (Ω) of said storage capacitor, “Don” denotes a duty ratio (%) of a load, “C” denotes a capacity (F) of a storage capacitor, and “Vo3” denotes an amount of a voltage drop (V) of a storage capacitor voltage occurring during a burst period.

6 more elements

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 having one terminal connected to a negative polarity, a source power controlling section to control a current fed from said power source section connected to an input terminal of said power controlling section, and to feed said current to a load connected to an output terminal of said power controlling section, and an energy storing section having a storage capacitor connected between said output terminal and said negative polarity, said method comprising:

a step of controlling a resistance value of a detecting resistor section having one terminal 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 a switching device according to a control signal produced by detecting a change in an input current based on a voltage across said detecting resistor section, and a voltage at said output terminal of a step-down DC—DC converter circuit comprising a switching device and a coil connected in series between another terminal of said detecting resistor and an output terminal, a capacitor connected between the output terminal and said negative polarity, and a diode connected between a connection point between said switching device and said coil and said negative polarity;
and
wherein a circuit constant of said source power controlling section, electrostatic capacity and internal resistance of said storage capacitor are determined by following equations:
T1+T2≦Tload
where “T1+T2” denotes a flowing period (Sec) of a power current and “Tload” denotes a load period (Sec):
Vo/2≧IC×{Rc+(Tload×Don)/(C×100)}=Vo3
where “Vo” denotes a voltage (V) of said storage capacitor when there is no load current, “IC” denotes a current (A) of said storage capacitor, “Rc” denotes an internal resistance (Ω) of said storage capacitor, “Don” denotes a duty ratio (%) of a load, “C” denotes a capacity (F) of a storage capacitor, and “Vo3” denotes an amount of a voltage drop (V) of a storage capacitor voltage occurring during a burst period.

6 more elements

Dependencies are inferred from the claim text.