US 10,462,859 B2
Clocked flyback converter circuit
Andre Mitterbacher, Dornbirn (AT)
Assigned to TRIDONIC GMBH & CO KG, Dornbirn (AT)
Appl. No. 15/570,407
Filed by TRIDONIC GMBH & CO KG, Dornbirn (AT)
PCT Filed Jun. 6, 2016, PCT No. PCT/AT2016/050178
§ 371(c)(1), (2) Date Oct. 30, 2017,
PCT Pub. No. WO2016/197168, PCT Pub. Date Dec. 15, 2016.
Claims priority of application No. 10 2015 210 710 (DE), filed on Jun. 11, 2015.
Prior Publication US 2018/0153010 A1, May 31, 2018
Int. Cl. H05B 33/08 (2006.01); H02M 3/335 (2006.01)
CPC H05B 33/0815 (2013.01) [H05B 33/0845 (2013.01); H02M 3/33507 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A clocked flyback converter circuit for operating one or more lighting means (11), comprising:
a controllable switch (7);
a transformer (5) having a primary winding (4), which is coupled to the controllable switch (7), and a secondary winding (6), to which lighting means (11) can be coupled;
a control device (14) for activating the switch (7); and
means (8) for direct or indirect recording of the current through the switch (7) in the switched-on state, and for supplying a signal reflecting this current to the control unit (14);
wherein the control unit (14) is configured to switch the switch (7) off when the signal reflecting the current has reached a variable switch-off threshold (Is), to modify the switch-off threshold (Is) for modifying the power transmitted by the flyback converter circuit (3) but not below a minimum value (Imin), and to switch from operation in the limit mode to operation in a discontinuous mode in order to obtain a further reduction of the power transmitted by the flyback converter circuit (3) where the minimum value (Imin) serves as a fixed switch-off threshold; and wherein the transformer (5) has a primary-side auxiliary winding (15), to which the control unit (14) is coupled in order to record a voltage curve over the auxiliary winding (15), and the control unit (14) switches the switch back on when operating in the discontinuous mode at a point in time at which the voltage is at a zero crossing after a local minimum in the voltage curve; and further wherein a dimming signal (D) can be sent to the control unit (14), and the control unit is configured to modify the switch-off threshold (Is) in accordance with the dimming signal in the limit mode, and is configured to modify the point in time of switching the switch back on in accordance with the dimming signal (D) in the discontinuous mode when the minimum value (Imin) serves as the fixed switch off threshold.