Converter control

• US 20020190698A1
• Filed: 10/25/2001
• Published: 12/19/2002
• Est. Priority Date: 10/27/2000
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Duerbaum, Thomas, Smidt, Pieter Jan Mark
• Granted Patent: US 6,717,388 B2
• Time in Patent Office: Days
• US Class Current: 323/222
• CPC Class Codes: H02M 3/33584 Bidirectional converters

Abstract

A buck converter, boost converter or flyback converter is generally represented as a two-port having a primary side with a primary switching device (10; 38; 70; 98; 110), and a secondary side with a secondary switching device (20; 50; 80; 106). The primary switching device is controlled in such a way that the on-time is adapted to the voltage at the primary side of the converter. The relation between the on-time of the primary switching device and the primary voltage is a generally hyperbolic function.

Claims

1. A method of controlling the conversion of a primary voltage supplied to a primary port (2;

32;

62;

90;

122) of a converter to a secondary voltage supplied to a secondary port (4;

34;

64;

92) of the converter, the converter further comprising a primary switching device (10;

38;

70;

98;

110) coupled in series with the primary port, and a secondary switching device (20;

50;

80;

106) coupled in series with the secondary port, characterized in that the on-time of the primary switching device is controlled by the primary voltage.

2. A method as claimed in to claim 1, wherein the on-time of the primary switching device (10;

38;

70;

98;

110) decreases when the primary voltage increases.

3. A method as claimed in to claim 1 or 2, wherein the on-time of the primary switching device (10;

38;

70;

98;

110) varies as a generally hyperbolic function as a function of the primary voltage.

4. A method as claimed in claim 1, wherein the secondary switching device (10;

38;

70;

98;

110) is controlled to reflect excessive power to the primary side.

5. A converter for converting a primary voltage supplied to a primary port (2;

32;

62;

90;

122) to a secondary voltage supplied to a secondary port (4;

34;

64;

92), the converter comprising a primary switching device (10;

38;

70;

98;

110) coupled in series with the primary port, a secondary switching device (20;

50;

80;

106) coupled in series with the secondary port, primary switching control means (12;

44;

72;

100) for controlling the switching of the primary switching device, and secondary switching control means (22;

52;

82;

108) for controlling the switching of the secondary switching device, characterized in that the primary switching control means is adapted to control the on-time of the primary switching device by the primary voltage.

6. A converter as claimed in claim 5, wherein the on-time of the primary switching device (10;

38;

70;

98;

110) decreases when the primary voltage increases.

7. A converter as claimed in claim 5 or 6, wherein the on-time of the primary switching device (10;

38;

70;

98;

110) varies as a generally hyperbolic function as a function of the primary voltage.

8. A converter as claimed in claim 5, wherein the primary switching device (10;

38;

70;

98;

110) and/or the secondary switching device (20;

50;

80;

106) comprises a MOSFET (110).

9. A converter as claimed in claim 5, comprising a transformer (96) with a primary winding (94) being connected in series with the primary port (2;

32;

62;

90;

122), and a secondary winding (102) being connected in series with the secondary port (4;

34;

64;

92).

10. A converter as claimed in claim 5, wherein the converter is a buck converter.

11. A converter as claimed in claim 5, wherein the converter is a boost converter.

12. A converter as claimed in claim 5, wherein the converter is a flyback converter.

14. A display apparatus comprising a converter as claimed in claim 5.

13. A control circuit (12;

44;

72;

100) for controlling a primary switching device (10;

38;

70;

98;

110) coupled in series with a primary port (2;

32;

62;

90;

122) of a converter, the control circuit comprising;

a control input for inputting a control variable; and

a control output for driving the primary switching device,

characterized in that the control variable is a primary voltage applied at the primary port of the converter, the control circuit being adapted to control the on-time of the primary switching device through the control output on the basis of the primary voltage.