Back to results
US 6,388,902 B1Granted
Switching power supply circuit
AssigneeSony Corporation
InventorMasayuki Yasumura
Life of this patent
Estimating the term…
Abstract
A switching power supply circuit is disclosed which allows selective use of a switching element having a comparatively low voltage withstanding property and a low current capacity and can be produced in a low lost and with a small size. Upon starting of power supply, the switching frequency of the switching element is raised by a soft starting circuit to increase a period of time until a secondary side DC output voltage reaches a steady level thereof As a result, the levels of a resonance voltage and a collector current obtained when the switching element starts its switching operation are suppressed.
Claims15
A switching power supply circuit, comprising:
- rectifier smoothing means for receiving a commercial ac power supply as an input and producing and outputting a rectified smoothed DC voltage;
- switching means for providing a switched output, said switching means comprising:
- a switching element for receiving and switchably outputting the DC voltage;
- a self-excited oscillation drive circuit for switchably driving said switching element in a self-excited manner;
- an insulating converter transformer for transmitting the output of said switching means to a secondary winding side of said switching power supply circuit;
- a primary winding side resonance circuit formed at least from a leakage inductance component including a primary winding of said insulating converter transformer and a capacitance of a resonance capacitor, said primary winding side resonance circuit operating said switching means in a resonance type operation;
- and
- a secondary winding side resonance circuit formed on the secondary winding side of said switching power supply circuit, including a leakage inductance component of a secondary winding of said insulating converter transformer and a capacitance of a secondary side resonance capacitor;
- DC output voltage production means, including said secondary side resonance circuit, for receiving an alternating voltage obtained at said secondary winding of said insulating converter transformer as an input thereto and performing a full-wave rectification operation for the input alternating voltage to produce a secondary winding side DC output voltage;
- switching frequency variation means for varying an inductance of said self excited oscillation drive circuit in response to a control current level supplied thereto to vary a switching frequency of said switching element;
- constant voltage control means for varying the control current in response to the level of the secondary winding side DC output voltage and supplying the varied control current to said switching frequency variation means to variably control the switching frequency thereby to effect constant voltage control for the secondary side DC output voltage;
- and
- switching frequency control means for receiving a start-up power supply obtained upon, or immediately after start up of said switching power supply circuit as an input thereto and for supplying a control current of a predetermined level over a predetermined period of time after start-up in place of said constant voltage control means to control the switching frequency so that the switching frequency remains within a predetermined range.
10 more elements
A switching power supply circuit, comprising:
- a rectifier smoother for receiving a commercial ac power supply as an input and producing and outputting a rectified smoothed DC voltage;
- a switch for providing a switched output, said switch comprising:
- a switching element for receiving and switchably outputting the DC voltage;
- and
- a self-excited oscillation drive circuit for switchably driving said switching element in a self-excited manner;
- an insulating converter transformer for transmitting the output of said switching means to a secondary winding side of said switching power supply circuit;
- a primary winding side resonance circuit formed at least from a leakage inductance component including a primary winding of said insulating converter transformer and a capacitance of a resonance capacitor, said primary winding side resonance circuit operating said switch in a resonance type operation;
- and
- a secondary winding side resonance circuit formed on the secondary winding side of said switching power supply circuit, including a leakage inductance component of a secondary winding of said insulating converter transformer and a capacitance of a secondary side resonance capacitor;
- DC output voltage producer, including said secondary side resonance circuit, for receiving an alternating voltage obtained at said secondary winding of said insulating converter transformer as an input thereto and performing a full-wave rectification operation for the input alternating voltage to produce a secondary winding side DC output voltage;
- a switching frequency varier for varying an inductance of said self-excited oscillation drive circuit in response to a control current level supplied thereto to vary a switching frequency of said switching element;
- a constant voltage controller for varying the control current in response to the level of the secondary winding side DC output voltage and supplying the varied control current to said switching frequency varier means to variably control the switching frequency thereby to effect constant voltage control for the secondary side DC output voltage;
- and
- a switching frequency controller for receiving a start-up power supply obtained upon, or immediately after start up of said switching power supply circuit as an input thereto and for supplying a control current of a predetermined level over a predetermined period of time after start-up in place of said constant voltage controller to control the switching frequency so that the switching frequency remains within a predetermined range.
11 more elements
A switching power supply method, comprising the steps of:
- receiving a commercial ac power supply by a rectifier smoother as an input;
- producing and outputting a rectified smoothed DC voltage;
- providing a switched output by a switcher, said switcher comprising:
- a switching element for receiving and switchably outputting the DC voltage;
- a self-excited oscillation drive circuit for switchably driving said switching element in a self-excited manner;
- an insulating converter transformer for transmitting the output of said switching means to a secondary winding side of said switching power supply circuit;
- a primary winding side resonance circuit formed at least from a leakage inductance component including a primary winding of said insulating converter transformer and a capacitance of a resonance capacitor, said primary winding side resonance circuit operating said switching means in a resonance type operation;
- and
- a secondary winding side resonance circuit formed on the secondary winding side of said switching power supply circuit, including a leakage inductance component of a secondary winding of said insulating converter transformer and a capacitance of a secondary side resonance capacitor;
- receiving an alternating voltage as an input to a DC output voltage producer, including said secondary side resonance circuit, obtained at said secondary winding of said insulating converter transformer;
- performing a full-wave rectification operation for the input alternating voltage to produce a secondary winding side DC output voltage;
- varying an inductance of said self-excited oscillation drive circuit by a switching frequency varier in response to a control current level supplied thereto to vary a switching frequency of said switching element;
- varying the control current in response to the level of the secondary winding side DC output voltage;
- supplying the varied control current to said switching frequency varier to variably control the switching frequency thereby to effect constant voltage control for the secondary side DC output voltage;
- and
- receiving a start-up power supply by a switching frequency controller obtained upon or immediately after start up of said switching power supply circuit as an input thereto and for supplying a control current of a predetermined level over a predetermined period of time after start-up in place of said supplied control current to control the switching frequency so that it remains within a predetermined range.
13 more elements
A switching power supply circuit including a resonance type converter, comprising:
- switching frequency control means for receiving a start-up power supply obtained upon, or immediately after start-up of said switching power supply circuit as an input obtained thereto;
- and
- means for supplying a control current of a predetermined level over a predetermined period of time after start-up in place of a voltage control signal to control a switching frequency of a switching element so that the switching frequency remains within a predetermined range,
- whereby said switching frequency is raised immediately after start-up and gradually decreased thereafter.
1 more element
A switching power supply circuit including a resonance type converter, comprising:
- a switching frequency controller for receiving a start-up power supply obtained upon, or immediately after start-up of said switching power supply circuit as an input obtained thereto;
- and
- a supplier for supplying a control current of a predetermined level over a predetermined period of time after start-up in place of a voltage control signal to control a switching frequency of a switching element so that the switching frequency remains within a predetermined range,
- whereby said switching frequency is raised immediately after start-up and gradually decreased thereafter.
1 more element
A switching power supply method employing a resonance type converter, comprising the steps of:
- receiving as an input a start-up power supply obtained on, or immediately after start-up;
- and
- supplying a control current of a predetermined level over a predetermined period of time after start-up in place of a voltage control signal to control a switching frequency of a switching element so that the switching frequency remains within a predetermined range,
- whereby said switching frequency is raised immediately after start-up and gradually decreased thereafter.
1 more element
Dependencies are inferred from the claim text.