Wide range zero voltage switching resonance type converter

• US 20020080635A1
• Filed: 11/30/2001
• Published: 06/27/2002
• Est. Priority Date: 12/07/2000
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Yasumura, Masayuki
• Granted Patent: US 6,590,787 B2
• Time in Patent Office: Days
• US Class Current: 363/97
• CPC Class Codes: H02M 3/3385 with automatic control of output voltage or current H02M3/33561 takes precedence
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

In a complex resonance type converter provided with a voltage resonance type converter on the primary side and a resonant circuit on the secondary side for supplying a plurality of direct-current output voltages from the secondary side, an inductance is connected in parallel with a primary winding of an isolating converter transformer. A switching output current is thereby distributed to the primary winding of the isolating converter transformer and the inductance, and a current flowing to a switching device and a damper diode inserted in parallel with the switching device has a normal waveform regardless of the level of load current of the secondary-side direct-current output. Therefore, stable ZVS operation can be ensured.

Claims

1. A switching power supply circuit comprising:

a switching means including a switching device driven by switching driving for performing switching operation on a direct-current input voltage inputted thereto;

a first isolating converter transformer having a primary-side winding and a plurality of secondary-side windings for transmitting an output of said switching means obtained in said primary-side winding to said plurality of secondary-side windings;

a primary-side parallel resonant circuit formed by said primary-side winding and a primary-side parallel resonant capacitor for converting operation of said switching means into voltage resonance type operation;

an inductance connected in parallel with said primary-side winding;

a secondary-side resonant circuit formed by connecting a secondary-side resonant capacitor in parallel with a first secondary-side winding of said plurality of secondary-side windings;

a first direct-current output voltage generating means for providing a first secondary-side direct-current output voltage by performing rectifying operation on an alternating voltage obtained in said first secondary-side winding and inputted to said first direct-current output voltage generating means; and

a second direct-current output voltage generating means for providing a second secondary-side direct-current output voltage by performing rectifying operation on an alternating voltage obtained in another secondary-side winding than said first secondary-side winding and inputted to said second direct-current output voltage generating means, and for supplying more load power than said first direct-current output voltage generating means.

2. The switching power supply circuit as claimed in claim 1, wherein said inductance is a choke coil.

3. The switching power supply circuit as claimed in claim 1,

wherein said inductance is a primary-side winding of a second isolating converter transformer;

and

said switching power supply circuit includes third direct-current voltage generating means for providing secondary-side direct-current output voltage by performing rectifying operation on an alternating voltage that is obtained in a secondary-side winding of said second isolating converter transformer by transmitting the output of said switching means obtained in the primary-side winding of said second isolating converter transformer to the secondary-side winding of said second isolating converter transformer, and is then inputted to said second direct-current output voltage generating means.

4. The switching power supply circuit as claimed in claim 1,

wherein said inductance is a primary winding of a high voltage output transformer;

and

said switching power supply circuit includes high direct-current voltage generating means for receiving a stepped-up alternating voltage having a required high voltage level, and generating and outputting a high direct-current voltage having a required high voltage level, said stepped-up alternating voltage being induced by said high-voltage primary winding and thereby induced in a secondary winding of said high voltage output transformer.

5. The high-voltage stabilizing circuit as claimed in claim 4,

wherein said secondary winding is divided into a plurality of secondary windings;

and

said high direct-current voltage generating means includes a multistage rectifier circuit formed by inserting a rectifier diode in series with each of said plurality of divided secondary windings for rectifying said stepped-up alternating voltage and a smoothing capacitor for smoothing a rectified output of said multistage rectifier circuit, thereby generating and outputting the high direct-current voltage having the required high voltage level.

6. The switching power supply circuit as claimed in claim 4, further comprising constant-voltage control means for effecting constant-voltage control on said high direct-current voltage by controlling switching frequency of the switching device of said switching means according to level of said high direct-current voltage.

7. The switching power supply circuit as claimed in claim 4, further comprising:

an active clamp circuit having an auxiliary switching device for clamping the alternating voltage obtained in said secondary-side resonant circuit; and

a constant-voltage control means for effecting constant-voltage control on said first secondary-side direct-current output voltage by variably controlling a conduction angle of said auxiliary switching device according to level of said first secondary-side direct-current output voltage.