Transformer, multi-output switching power supply, liquid crystal television

• US 7,486,066 B2
• Filed: 08/02/2006
• Issued: 02/03/2009
• Est. Priority Date: 08/02/2005
• Status: Expired due to Fees

• Current Assignee: Funai Electric Co., Ltd.
• Original Assignee: Funai Electric Co., Ltd.
• Inventors: Nagamune, Atsuhiko
• Primary Examiner(s): Patel; Rajnikant B
• Application Number:
  US11/497,777
• Publication Number:
  US 20070030404A1
• Time in Patent Office: 916 Days
• Field of Search: 363/21.04, 363/21.07, 363/21.12, 363/21.16, 363/21.18, 363/19, 363/23, 363/26, 363/79, 363/97, 363/21.02, 336/69, 336/84.R, 336/84.C, 336/182, 336/185, 336/411, 336/232, 336/225, 336/174, 315/204, 315/207, 315/224, 315/246, 315/291, 307/327, 307/66, 307/64, 323/346, 323/357, 323/358
• US Class Current: 323/346
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers
• CPC Class Codes: H04N 5/63 Generation or supply of power specially adapted for television receivers

Abstract

The present invention aims to obtain a stable output voltage without requiring an extra circuit by suppressing influence of noise of the primary winding and voltage induction by leakage inductance. In a transformer 3 used in a multi-output switching power supply, a secondary winding S1 for outputting a voltage to be fed back to the primary side out of the secondary windings S2 to Sn winded on a bobbin 3a is divided into a first layer S1a and a second layer S1b, a secondary winding S2 to Sn for outputting a voltage not fed back to the primary side is winded between the first layer S1a and the second layer S1b, and the first layer S1a and the second layer S1b is regular winded.

Claims

1. A liquid crystal television comprising:

a tuner;

a signal processing part for processing a television signal extracted at the tuner;

a liquid crystal panel for displaying a predetermined picture based on a picture signal processed in the signal processing part;

a back light for illuminating the liquid crystal panel;

a voice output part for outputting voice based on a voice signal processed in the signal processing part; and

a power supply circuit for supplying voltage to each part, the power supply circuit being a multi-output switching power supply including;

a rectifying circuit for rectifying an AC voltage;

a transformer to which primary winding an output of the rectifying circuit is provided with and from which secondary winding a plurality of voltages supplied to each part is taken out;

a switching element connected to the primary winding of the transformer;

a feedback circuit for feeding back a predetermined voltage taken out from the secondary winding; and

a switching control circuit for controlling the operation of the switching element based on the output of the feedback circuit,

wherein a secondary winding for outputting a voltage fed back by the feedback circuit out of the secondary windings winded on a bobbin of the transformer is divided into a first layer and a second layer, and wherein a secondary winding for outputting a voltage not fed back is arranged between the first layer and the second layer.

2. A transformer for multi-output switching power supply in which an output of a rectifying circuit is supplied to a primary winding, a plurality of voltages are taken out from a secondary winding, and a predetermined voltage taken out is fed back to the primary side, and the operation of a switching element connected to the primary winding is controlled based on the feed back,

wherein a secondary winding for outputting a voltage to be fed back out of the secondary windings winded around a bobbin is divided into a first layer and a second layer, and wherein a secondary winding for outputting a voltage not fed back is arranged between the first layer and the second layer.

3. The transformer according to claim 2, wherein the secondary winding forming the first layer and the second layer has no gap between individual turns of the winding.

4. A multi-output switching power supply comprising:

a rectifying circuit for rectifying an AC voltage;

a transformer to which primary winding is provided with an output of the rectifying circuit and from which secondary winding a plurality of voltages are taken out;

a switching element connected to the primary winding of the transformer;

a feedback circuit for feeding back a predetermined voltage taken out from the secondary winding; and

a switching control circuit for controlling the operation of the switching element based on the output of the feedback circuit,

wherein a secondary winding for outputting a voltage fed back by the feedback circuit out of the secondary windings winded on a bobbin of the transformer is divided into a first layer and a second layer, and wherein a secondary winding for outputting a voltage not fed back is arranged between the first layer and the second layer.