US 2002/0001210 A1 · Switching power supply · patentgrep

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Abstract

In an isolation type DC-DC converter for performing full-wave rectification in the secondary of a transformer, two switching sections 11 and 13 alternately switch ON and OFF, thereby reversing the current I3 flowing through a primary winding 3a of the transformer 3. A switching control circuit 7 outputs switching signals G1 and G3 to the switching sections 11 and 13, respectively, thereby controlling the switching of the switching sections. A load current sensing section 9 senses the amount of load current, then compares it with a predetermined threshold value. When the amount of load current sensed is smaller than the threshold value, a delay circuit 8 delays the switching signals G1 and G3 to the switching sections 11 and 13 for a predetermined delay time. The delay time is set to be substantially equal to ¼ of the resonance period determined by the self-inductance of the primary winding 3a of the transformer 3.

Claims24

Dependent claims

A switching power supply comprising:

A) a DC-DC converter comprising:
a) four switching sections consisting of a first switching section, a second switching section, a third switching section, and a fourth switching section, each comprising 1) a switching device turned ON and OFF by switching signals from the outside, and 2) a diode and a capacitor each connected to said switching device in parallel;
b) a transformer comprising a primary winding and at least one secondary winding;
c) a rectifying circuit for performing full-wave rectification on the output of said transformer;
and
d) a smoothing circuit for smoothing the output of said rectifying circuit;
wherein
a) the end (cathode) of said first switching section on the cathode side of said diode and the cathode of said third switching section are connected to a high potential terminal of a substantially constant DC voltage source;
b) the cathode of said second switching section is connected to the end (anode) of said first switching section on the anode side of said diode, while the anode of said second switching section is connected to a low potential terminal of said substantially constant DC voltage source;
c) the cathode of said fourth switching section is connected to the anode of said third switching section, while the anode of said fourth switching section is connected to said low potential terminal of said substantially constant DC voltage source;
and
d) one end of said primary winding of said transformer is connected to the junction point between said first switching section and said second switching section, while the other end of said primary winding is connected to the junction point between said third switching section and said fourth switching section;
B) a switching control section for outputting said switching signals to said switching devices at a predetermined switching frequency;
C) a load current sensing section for sensing the amount of load current output from said DC-DC converter;
and
D) a delay section for delaying said switching signals of said switching control section for a predetermined delay time depending on said amount of load current sensed by said load current sensing section.

13 more elements

A switching power supply comprising:

A) a DC-DC converter comprising:
a) four switching sections consisting of a first switching section, a second switching section, a third switching section, and a fourth switching section, each comprising 1) a switching device turned ON and OFF by switching signals from the outside, and 2) a diode and a capacitor each connected to said switching device in parallel;
b) a first voltage dividing capacitor and a second voltage dividing capacitor interconnected in series;
c) a transformer comprising a primary winding and at least one secondary winding;
d) a rectifying circuit for performing full-wave rectification on the output of said transformer;
and
e) a smoothing circuit for smoothing the output of said rectifying circuit;
wherein
a) the opposite end of said first voltage dividing capacitor to the end thereof connected to said second voltage dividing capacitor is connected to a high potential terminal of a substantially constant DC voltage source;
b) the opposite end of said second voltage dividing capacitor to the end thereof connected to said first voltage dividing capacitor is connected to a low potential terminal of said substantially constant DC voltage source;
c) the cathode of said first switching section is connected to said high potential terminal of said substantially constant DC voltage source;
d) the cathode of said second switching section is connected to the anode of said first switching section, while the anode of said second switching section is connected to said low potential terminal of said substantially constant DC voltage source;
e) either the anodes or the cathodes of said third switching section and said fourth switching section are interconnected, while the opposite ends of said third switching section and said fourth switching section to the junction point thereof are connected to the respective ends of said primary winding of said transformer;
and
f) one end of said primary winding is connected to the junction point between said first switching section and said second switching section, while the other end of said primary winding is connected to the junction point between said first voltage dividing capacitor and said second voltage dividing capacitor;
B) a switching control section for outputting said switching signals to said switching devices at a predetermined switching frequency;
C) a load current sensing section for sensing the amount of load current output from said DC-DC converter;
and
D) a delay section for delaying said switching signals of said switching control section for a predetermined delay time depending on said amount of load current sensed by said load current sensing section.

16 more elements

A switching power supply comprising:

A) a DC-DC converter comprising:
a) four switching sections consisting of a first switching section, a second switching section, a third switching section, and a fourth switching section, each comprising 1) a switching device turned ON and OFF by switching signals from the outside, and 2) a diode and a capacitor each connected to said switching device in parallel;
b) a first voltage dividing capacitor and a second voltage dividing capacitor interconnected in series;
c) a transformer comprising a primary winding, at least one secondary winding, and an auxiliary winding;
d) a rectifying circuit for performing full-wave rectification on the output of said transformer;
and
e) a smoothing circuit for smoothing the output of said rectifying circuit;
wherein
a) the opposite end of said first voltage dividing capacitor to the end thereof connected to said second voltage dividing capacitor is connected to a high potential terminal of a substantially constant DC voltage source;
b) the opposite end of said second voltage dividing capacitor to the end thereof connected to said first voltage dividing capacitor is connected to a low potential terminal of said substantially constant DC voltage source;
c) the cathode of said first switching section is connected to said high potential terminal of said substantially constant DC voltage source;
d) the cathode of said second switching section is connected to the anode of said first switching section, while the anode of said second switching section is connected to said low potential terminal of said substantially constant DC voltage source;
e) either the anodes or the cathodes of said third switching section and said fourth switching section are interconnected, the junction point thereof is connected to said low potential terminal of said substantially constant DC voltage source, and the opposite ends of said third switching section and said fourth switching section to said junction point thereof are connected to the respective ends of said auxiliary winding;
and
f) one end of said primary winding is connected to the junction point between said first switching section and said second switching section, while the other end of said primary winding is connected to the junction point between said first voltage dividing capacitor and said second voltage dividing capacitor;
B) a switching control section for outputting said switching signals to said switching devices at a predetermined switching frequency;
C) a load current sensing section for sensing the amount of load current output from said DC-DC converter;
and
D) a delay section for delaying said switching signals of said switching control section for a predetermined delay time depending on said amount of load current sensed by said load current sensing section.

16 more elements

A switching power supply comprising:

A) a DC-DC converter comprising:
a) four switching sections consisting of a first switching section, a second switching section, a third switching section, and a fourth switching section, each comprising 1) a switching device turned ON and OFF by switching signals from the outside, and 2) a diode and a capacitor each connected to said switching device in parallel;
b) a transformer comprising a first primary winding and a second primary winding interconnected in series, and at least one secondary winding;
c) a rectifying circuit for performing full-wave rectification on the output of said transformer;
and
d) a smoothing circuit for smoothing the output of said rectifying circuit;
wherein
a) the junction point between said first primary winding and said second primary winding is connected to a first potential terminal of a substantially constant DC voltage source;
b) one end of said first switching section is connected to a second potential terminal of said substantially constant DC voltage source, while the other end of said first switching section is connected to the opposite end of said first primary winding to the end thereof connected to said second primary winding;
c) the end of said second switching section on the same side as the connected end of said first switching section to said second potential terminal of said substantially constant DC voltage source is connected to said second potential terminal of said substantially constant DC voltage source, while the other end of said second switching section is connected to the opposite end of said second primary winding to the end thereof connected to said first primary winding;
and
d) either the anodes or the cathodes of said third switching section and said fourth switching section are interconnected, and the opposite ends of said third switching section and said fourth switching section to the junction point thereof are connected to the respective ends of said first primary winding and said second primary winding opposite to the junction point thereof;
B) a switching control section for outputting said switching signals to said switching devices at a predetermined switching frequency;
C) a load current sensing section for sensing the amount of load current output from said DC-DC converter;
and
D) a delay section for delaying said switching signals of said switching control section for a predetermined delay time depending on said amount of load current sensed by said load current sensing section.

13 more elements

A switching power supply comprising:

A) a DC-DC converter comprising:
a) four switching sections consisting of a first switching section, a second switching section, a third switching section, and a fourth switching section, each comprising 1) a switching device turned ON and OFF by switching signals from the outside, and 2) a diode and a capacitor each connected to said switching device in parallel;
b) a transformer comprising a first primary winding and a second primary winding interconnected in series, at least one secondary winding, and an auxiliary winding;
c) a rectifying circuit for performing full-wave rectification on the output of said transformer;
and
d) a smoothing circuit for smoothing the output of said rectifying circuit;
wherein
a) the junction point between said first primary winding and said second primary winding is connected to a first potential terminal of a substantially constant DC voltage source;
b) one end of said first switching section is connected to a second potential terminal of said substantially constant DC voltage source, while the other end of said first switching section is connected to the opposite end of said first primary winding to the end thereof connected to said second primary winding;
c) the end of said second switching section on the same side as the connected end of said first switching section to said second potential terminal of said substantially constant DC voltage source is connected to said second potential terminal of said substantially constant DC voltage source, while the other end of said second switching section is connected to the opposite end of said second primary winding to the end thereof connected to said first primary winding;
and
d) either the anodes or the cathodes of said third switching section and said fourth switching section are interconnected, the junction point thereof is connected to said second potential terminal of said substantially constant DC voltage source, and the opposite ends of said third switching section and said fourth switching section to said junction point thereof are connected to the respective ends of said auxiliary winding;
B) a switching control section for outputting said switching signals to said switching devices at a predetermined switching frequency;
C) a load current sensing section for sensing the amount of load current output from said DC-DC converter;
and
D) a delay section for delaying said switching signals of said switching control section for a predetermined delay time depending on said amount of load current sensed by said load current sensing section.

13 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/867,038Filed 29 May 2001
Priority: JP 2000-1651331 Jun 2000
Published: 3 Jan 2002
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

H02M 3/3376
In push-pull configuration: with automatic control of output voltage or current
H02M 1/0058
Transistor switching losses: by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current…
H02M 1/38
Details of apparatus for conversion: means for preventing simultaneous conduction of switches
Y02B 70/10
Technologies for an efficient end-user side electric power management and consumption: technologies improving the efficiency by using…

Family

US 6,452,816 B2Related patent
US 2002/0001210 A1This patent

From the US filing history. Foreign family members aren’t listed.

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