METHOD FOR CONTROLLING A POWER FACTOR CORRECTION CIRCUIT, POWER FACTOR CORRECTION CIRCUIT AND OPERATING DEVICE FOR AN ILLUMINANT

• US 20150054421A1
• Filed: 04/15/2013
• Published: 02/26/2015
• Est. Priority Date: 04/13/2012
• Status: Active Grant

• Current Assignee: Tridonic GmbH & Co. KG (Zumtobel Group AG)
• Original Assignee: Tridonic GmbH & Co. KG (Zumtobel Group AG)
• Inventors: Auer, Hans, Lampert, Peter
• Granted Patent: US 10,447,146 B2
• Time in Patent Office: Days
• US Class Current: 315/247
• CPC Class Codes: H02M 1/0032 Control circuits allowing low power mode operation, e.g. in standby mode
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 1/4241 using a resonant converter
• CPC Class Codes: H02M 7/06 using discharge tubes without control electrode or semiconductor devices without control electrode
• CPC Class Codes: H05B 41/28 using static converters
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: H05B 47/10 Controlling the light source
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
• 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

For the purpose of power factor correction, an inductance (21) is supplied with an input voltage (Vin), wherein a controllable switching means (24) that is coupled to the inductance (21) is actuated in order to selectively charge and discharge the inductance (21). A control device (14) for actuating the switching means (24) is designed such that it actuates the switching means (24) selectively on the basis of one of a plurality of modes of operation. In a first mode of operation, a switch-on time is stipulated for the switching means (24) on the basis of a minimum waiting time and on the basis of a voltage that drops across the switching means (24).

Claims

1. A method for controlling a power factor correction circuit (11, 14;

20) for an illuminant (3), the power factor correction circuit (11, 14;

20) having an inductance (21) coupled to an input, and a controllable switch (24) coupled to the inductance (21), in order optionally to charge and to discharge the inductance (21) by the closing and opening of the switch (24), wherein the method comprises;

selecting an operating mode for controlling the switching means (24) from a plurality of operating modes, and

controlling the switch (24) in accordance with the selected operating mode, wherein in a first operating mode

a minimum waiting time (69) between the switching-off of the switch (24) and renewed switching-on of the switching means (24) is determined and

a switch-on instant (68) for the switching means (24) is defined depending on the minimum waiting time (69) and depending on a voltage (66;

70) dropped across the switch (24).

2. The method as claimed in claim 1, wherein in the first operating mode the switch-on instant (68) is defined depending on a temporal profile of the voltage (66;

70) dropped across the switch (24).

3. The method as claimed in claim 1, wherein in the first operating mode at least one time window (84-86) is determined depending on an instant at which the voltage (66;

70) dropped across the switch (24) has a local extremum).

4. The method as claimed in claim 3, wherein a measurement variable (66, 76, 81) indicating a current (66, 76) flowing through the inductance (21) or a zero crossing of the current (66, 76) flowing through the inductance (21) is compared with a reference value (82) and, depending on a result of the comparison, it is ascertained whether the voltage (66;

70) dropped across the switch (24) has a local extremum.

5. The method as claimed in claim 4, wherein the at least one time window (84-86) is determined depending on an instant at which a difference between the measurement variable (81) and the reference value (82) has a change of sign in a predefined direction.

6. The method as claimed in claim 4, wherein the reference value (82) is chosen such that it indicates a zero crossing of the current (66, 76) flowing through the inductance (21).

7. The method as claimed in claim 3, wherein the at least one time window (84-86) for switching on the switch (24) is determined such that the switch (24) is switched on again if a voltage (66;

70) dropped across a drain-source path of the switch (24) attains a local minimum (67).

8. The method as claimed in claim 1, wherein the minimum waiting time (69) is determined depending on the load at the output (22) of the power factor correction circuit (11, 14;

20) or depending on an output power.

9. The method as claimed in claim 1, wherein in a second operating mode a switch-on instant (68) at which the switching means (24) is switched on is defined independently of the minimum waiting time (69).

10. The method as claimed in claim 9, wherein the first operating mode is a DCM operating mode and the second operating mode is a CCM operating mode or BCM operating mode.

11. The method as claimed in claim 1, wherein the first operating mode is only activated if the load or an output power is less than a threshold value (92).

12. A power factor correction circuit (11, 14;

20) for an illuminant (3), the power factor correction circuit (11, 14, 20) comprising

an inductance (21) coupled to an input of the power factor correction circuit (11, 14;

20), a controllable switching means (24) coupled to the inductance (21), and

a control device (14) for controlling the switching means (24), in order optionally to charge and to discharge the inductance (21) by controlling the switch (24), wherein the control device (14) is configured to select an operating mode from a plurality of operating modes and to control the switch (24) in accordance with the selected operating mode,

wherein the control device (14) is configured to determine in a first operating mode a minimum waiting time (69) between switching-off of the switching means (24) and renewed switching-on of the switch (24) and to define a switch-on instant (68) for the switch (24) depending on the minimum waiting time (69) and depending on a voltage (66;

70) dropped across the switch (24).

13. The power factor correction circuit (11, 14;

20) as claimed in claim 12, which is configured for carrying out a method for controlling a power factor correction circuit (11, 14;

20) for an illuminant (3), the power factor correction circuit (11, 14;

20) having an inductance (21) coupled to an input, and a controllable switch (24) coupled to the inductance (21), in order optionally to charge and to discharge the inductance (21) by the closing and opening of the switch (24), wherein the method comprises;

selecting an operating mode for controlling the switching means (24) from a plurality of operating modes, and

controlling the switch (24) in accordance with the selected operating mode, wherein in a first operating mode

a minimum waiting time (69) between the switching-off of the switch (24) and renewed switching-on of the switching means (24) is determined and

a switch-on instant (68) for the switching means (24) is defined depending on the minimum waiting time (69) and depending on a voltage (66;

70) dropped across the switch (24).

14. An operating device (2) for an illuminant (3), comprising the power factor correction circuit (11, 14;

20) as claimed in claim 12.