Switching power supply circuit
First Claim
1. A switching power supply circuit which includes a rectification section for rectifying an AC input voltage and a smoothing section for smoothing the rectification voltage from said rectification section, and a first switching converter section and a second switching converter section for receiving and operating with the smoothed voltage from said smoothing section as a DC input voltage, said first and second switching converter sections being activated at different timings from each other when to be activated, whereineach of the plurality of switching converter sections includes:
- a switching section for receiving the DC input voltage to perform switching operation, said switching section being formed from a high side switching element and a low side switching element connected in a half-bridge connection;
a switching driving section for switching driving the switching elements;
an insulating converter transformer formed by winding at least a primary winding to which a switching output obtained by the switching operation of said switching section is supplied and a secondary winding in which an alternating voltage as a switching output obtained in said primary winding is excited;
a primary side series resonance circuit formed at least from a leakage inductance component of said primary winding of said insulating converter transformer and a capacitance of a primary side series resonance capacitor connected in series to said primary winding for making operation of said switching section that of a current resonance type;
a primary side partial voltage resonance circuit formed from a capacitance of a partial voltage resonance capacitor connected in parallel to one of the two switching elements each of which forms the half bridge connection and a leakage inductance component of said primary winding of said insulating converter transformer, voltage resonance operation of said primary side partial voltage resonance circuit being obtained only in response to each of timings at which each of said switching elements turns on and turns off;
a DC output voltage production section for receiving a secondary side AC voltage obtained by said secondary winding of said insulating converter transformer and performing rectification operation of the received secondary side AC voltage to produce a plurality of secondary side DC output voltages;
a frequency control type fixed voltage control section for controlling said switching driving section in response to a level of a required one of the plurality of secondary side DC output voltages to vary the switching frequency of said switching section to perform fixed voltage control for the required one of the secondary side DC output voltages;
an inductance control type fixed voltage control section provided for each of required ones of the secondary side DC output voltages which are required to be fixed voltages other than the required one of the secondary side DC output voltages which is an object of the fixed voltage control by said frequency control type fixed voltage control section, said inductance control type fixed voltage control section being configured such that a controlled winding of a control transformer in the form of a saturable reactor having a control winding and said controlled winding wound thereon is inserted in a secondary side rectification current path for producing the secondary side DC output voltage and a control current level to be supplied to said control winding is varied in response to the inputted secondary side DC output voltage level to vary the inductance of the controlled winding thereby to perform fixed voltage control for the secondary side DC output voltage; and
a power factor improving circuit including a power factor improving transformer formed by winding a power factor improving primary winding inserted in series in said primary side series resonance circuit and a power factor improving secondary winding inserted in a rectification current path formed as said rectification smoothing section and a rectification element inserted in a required location of said rectification current path for performing switching operation based on an excited voltage excited in said power factor improving secondary winding by said power factor improving primary winding to interrupt the rectification current for improving the power factor;
said first switching converter section including a first switch section for operating, at a timing after predetermined time elapses after a predetermined secondary side DC output voltage rises, to change over a secondary side rectification current path for producing another predetermined secondary side DC output voltage from an off state to an on state.
1 Assignment
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Accused Products
Abstract
A switching power supply circuit includes a plurality of switching converters, each including a partial resonance voltage circuit combined with a current resonance type switching converter using a half-bridge connection system. For changeover control, a rectification circuit serves as a voltage doubler rectification circuit at an AC voltage less than or equal to 150V, but serves as a full-wave rectification circuit at an AC voltage greater than or equal to 150V. The voltage output of the converters is fed back to a rectification current path by a power factor improving transformer, the rectification current being interrupted by means of a rectification diode to expand the conduction angle of the AC input current. A DC switch circuit in the rectification current path is switched between on and off conditions in response to the input of a predetermined starting signal to control the starting order of the secondary side DC output voltage.
24 Citations
7 Claims
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1. A switching power supply circuit which includes a rectification section for rectifying an AC input voltage and a smoothing section for smoothing the rectification voltage from said rectification section, and a first switching converter section and a second switching converter section for receiving and operating with the smoothed voltage from said smoothing section as a DC input voltage, said first and second switching converter sections being activated at different timings from each other when to be activated, wherein
each of the plurality of switching converter sections includes: -
a switching section for receiving the DC input voltage to perform switching operation, said switching section being formed from a high side switching element and a low side switching element connected in a half-bridge connection; a switching driving section for switching driving the switching elements; an insulating converter transformer formed by winding at least a primary winding to which a switching output obtained by the switching operation of said switching section is supplied and a secondary winding in which an alternating voltage as a switching output obtained in said primary winding is excited; a primary side series resonance circuit formed at least from a leakage inductance component of said primary winding of said insulating converter transformer and a capacitance of a primary side series resonance capacitor connected in series to said primary winding for making operation of said switching section that of a current resonance type; a primary side partial voltage resonance circuit formed from a capacitance of a partial voltage resonance capacitor connected in parallel to one of the two switching elements each of which forms the half bridge connection and a leakage inductance component of said primary winding of said insulating converter transformer, voltage resonance operation of said primary side partial voltage resonance circuit being obtained only in response to each of timings at which each of said switching elements turns on and turns off; a DC output voltage production section for receiving a secondary side AC voltage obtained by said secondary winding of said insulating converter transformer and performing rectification operation of the received secondary side AC voltage to produce a plurality of secondary side DC output voltages; a frequency control type fixed voltage control section for controlling said switching driving section in response to a level of a required one of the plurality of secondary side DC output voltages to vary the switching frequency of said switching section to perform fixed voltage control for the required one of the secondary side DC output voltages; an inductance control type fixed voltage control section provided for each of required ones of the secondary side DC output voltages which are required to be fixed voltages other than the required one of the secondary side DC output voltages which is an object of the fixed voltage control by said frequency control type fixed voltage control section, said inductance control type fixed voltage control section being configured such that a controlled winding of a control transformer in the form of a saturable reactor having a control winding and said controlled winding wound thereon is inserted in a secondary side rectification current path for producing the secondary side DC output voltage and a control current level to be supplied to said control winding is varied in response to the inputted secondary side DC output voltage level to vary the inductance of the controlled winding thereby to perform fixed voltage control for the secondary side DC output voltage; and a power factor improving circuit including a power factor improving transformer formed by winding a power factor improving primary winding inserted in series in said primary side series resonance circuit and a power factor improving secondary winding inserted in a rectification current path formed as said rectification smoothing section and a rectification element inserted in a required location of said rectification current path for performing switching operation based on an excited voltage excited in said power factor improving secondary winding by said power factor improving primary winding to interrupt the rectification current for improving the power factor; said first switching converter section including a first switch section for operating, at a timing after predetermined time elapses after a predetermined secondary side DC output voltage rises, to change over a secondary side rectification current path for producing another predetermined secondary side DC output voltage from an off state to an on state. - View Dependent Claims (2, 3, 5, 6, 7)
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4. A first switching power supply circuit and another switching power supply circuit which include a rectification section for rectifying an AC input voltage and a smoothing section for smoothing the rectification voltage from said rectification section, and a plurality of switching converter sections for receiving and operating with the smoothed voltage from said smoothing section as a DC input voltage, one of said plurality of switching converter sections being activated at a timing determined in advance, wherein
each of the plurality of switching converter sections includes: -
a switching section for receiving the DC input voltage to perform switching operation, said switching section being formed from a high side switching element and a low side switching element connected in a half-bridge connection; a switching driving section for switching driving the switching elements; an insulating converter transformer formed by winding at least a primary winding to which a switching output obtained by the switching operation of said switching section is supplied and a secondary winding in which an alternating voltage as a switching output obtained in said primary winding is excited; a primary side series resonance circuit formed at least from a leakage inductance component of said primary winding of said insulating converter transformer and a capacitance of a primary side series resonance capacitor connected in series to said primary winding for making operation of said switching section that of a current resonance type; a primary side partial voltage resonance circuit formed from a capacitance of a partial voltage resonance capacitor connected in parallel to one of the two switching elements each of which forms the half bridge connection and a leakage inductance component of said primary winding of said insulating converter transformer, voltage resonance operation of said primary side partial voltage resonance circuit being obtained only in response to each of timings at which each of said switching elements turns on and turns off; a DC output voltage production section for receiving a secondary side AC voltage obtained by said secondary winding of said insulating converter transformer and performing rectification operation of the received secondary side AC voltage to produce a plurality of secondary side DC output voltages; a frequency control type fixed voltage control section for controlling said switching driving section in response to a level of a required one of the plurality of secondary side DC output voltages to vary the switching frequency of said switching section to perform fixed voltage control for the required one of the secondary side DC output voltages; an inductance control type fixed voltage control section provided for each of required ones of the secondary side DC output voltages which are required to be fixed voltages other than the required one of the secondary side DC output voltages which is an object of the fixed voltage control by said frequency control type fixed voltage control section, said inductance control type fixed voltage control section being configured such that a controlled winding of a control transformer in the form of a saturable reactor having a control winding and said controlled winding wound thereon is inserted in a secondary side rectification current path for producing the secondary side DC output voltage and a control current level to be supplied to said control winding is varied in response to the inputted secondary side DC output voltage level to vary the inductance of the controlled winding thereby to perform fixed voltage control for the secondary side DC output voltage; and a first switch section for changing over the secondary side rectification current path for producing another predetermined secondary side DC output voltage from an off state to an on state at the timing after lapse of a predetermined time after a predetermined secondary side DC output voltage rises; and a power factor improving circuit for improving the power factor; said power factor improving circuit including a power factor improving transformer formed by winding a power factor improving primary winding inserted in series in said primary side series resonance circuit and a power factor improving secondary winding inserted in a rectification current path formed as said rectification smoothing section and a rectification element inserted in a required location of the rectification current path for performing switching operation based on an excited voltage excited in said power factor improving secondary winding by said power factor improving primary winding to interrupt the rectification current.
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Specification