SWITCHING POWER SUPPLY DEVICE, SWITCHING POWER SUPPLY CONTROL METHOD, AND ELECTRONIC APPARATUS

• US 20140355315A1
• Filed: 05/22/2014
• Published: 12/04/2014
• Est. Priority Date: 05/29/2013
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Watanabe, Hiroyuki
• Granted Patent: US 9,882,498 B2
• Time in Patent Office: Days
• US Class Current: 363/21.09
• CPC Class Codes: H02M 1/4241 using a resonant converter
• CPC Class Codes: H02M 3/33546 with automatic control of the output voltage or current H02M3/33561 takes precedence
• CPC Class Codes: H02M 7/4815 Resonant converters H02M7/4811 and H02M7/4826 take precedence
• CPC Class Codes: H02M 7/523 with LC-resonance circuit in the main circuit
• 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

A switching power supply device includes a switching element to which a DC input is supplied, a frequency control circuit which controls a switching frequency of the switching element, a frequency detection circuit which detects the switching frequency of the switching element, and a duty ratio control circuit which controls a switching duty ratio based on the frequency detected by the frequency detection circuit. The duty ratio control circuit controls the switching duty ratio such that the switching frequency becomes an approximately maximum frequency.

Claims

1. A switching power supply device comprising:

a switching element to which a DC input is supplied;

a frequency control circuit which controls a switching frequency of the switching element;

a frequency detection circuit which detects the switching frequency of the switching element; and

a duty ratio control circuit which controls a switching duty ratio based on the frequency detected by the frequency detection circuit,

wherein the duty ratio control circuit controls the switching duty ratio such that the switching frequency becomes an approximately maximum frequency.

2. The switching power supply device according to claim 1,

wherein the duty ratio control circuit operates using the switching duty ratio in an area where a slope of a change of the switching frequency with respect to a change of the switching duty ratio becomes positive.

3. The switching power supply device according to claim 1, further comprising:

a transformer;

a resonance circuit; and

a rectification circuit,

wherein the switching element is configured by a first switching element and a second switching element which are connected in series and alternately turned on by the switching frequency,

wherein output currents of the first and second switching elements are supplied to the transformer,

wherein the resonance circuit is connected to a primary side of the transformer, and the rectification circuit is connected to a secondary side of the transformer, and

wherein an output voltage is stabilized by a frequency of the switching signal which is controlled by a feedback signal.

4. The switching power supply device according to claim 3,

wherein a time of changing the switching duty ratio is set so as to be longer than a response time which is determined from a band of the feedback signal.

5. The switching power supply device according to claim 1,

wherein the duty ratio control circuit typically performs a duty ratio control operation.

6. A switching power supply control method of a switching power supply device including a switching element to which a DC input is supplied, a frequency control circuit which controls a switching frequency of the switching element, a frequency detection circuit which detects the switching frequency of the switching element, and a duty ratio control circuit which controls a switching duty ratio based on the frequency detected by the frequency detection circuit, the method comprising:

causing the duty ratio control circuit to control the switching duty ratio such that the switching frequency becomes an approximately maximum frequency.

7. The switching power supply control method according to claim 6,

wherein the duty ratio control circuit operates using the switching duty ratio in an area where a slope of a change of the switching frequency with respect to a change of the switching duty ratio becomes positive.

8. An electronic apparatus comprising:

a switching power supply device,

wherein the switching power supply device includes,

a switching element to which a DC input is supplied;

a frequency control circuit which controls a switching frequency of the switching element;

a frequency detection circuit which detects the switching frequency of the switching element; and

a duty ratio control circuit which controls a switching duty ratio based on the frequency detected by the frequency detection circuit, and

wherein the duty ratio control circuit controls the switching duty ratio such that the switching frequency becomes an approximately maximum frequency.

9. The electronic apparatus according to claim 8,

wherein the duty ratio control circuit operates using the switching duty ratio in an area where a slope of a change of the switching frequency with respect to a change of the switching duty ratio becomes positive.