Dual switcher flyback structure for LED driver

A driver circuit configured to convert electrical power at an input voltage into electrical power at an output voltage;

• wherein the driver circuit comprises
• a first switcher stage comprising a primary winding of a transformer which is arranged in series with a first power switch;
• wherein the first switcher stage is arranged in parallel to the input voltage at an input of the driver circuit;
• a second switcher stage comprising an auxiliary winding of the transformer which is arranged in series with a second power switch;
• wherein the second switcher stage is arranged in parallel to a reservoir capacitor;
• a secondary winding of the transformer which is arranged in parallel to the output voltage at an output of the driver circuit;
• and
• controller configured to
• determine whether the input voltage is greater or smaller than a predetermined voltage threshold;
• operate the first switcher stage to transfer electrical power from the input of the driver circuit to the output of the driver circuit, during a first time period when the input voltage is greater than the predetermined voltage threshold;
• and
• operate the second switcher staqe to transfer electrical power from the reservoir capacitor to the output of the driver circuit, during a second time period when the input voltage is smaller than the predetermined voltage threshold.

A method controlling a power converter to convert electrical power at an input voltage into electrical power at an output voltage;

• wherein the power converter comprises a first switcher stage comprising a primary winding of a transformer which is arranged in series with a first power switch;
• wherein the first switcher stage is in parallel to the input voltage at an input of the power converter;
• a second switcher stage comprising an auxiliary winding of the transformer which is in series with a second power switch;
• wherein the second switcher stage is in parallel to a reservoir capacitor;
• and a secondary winding of the transformer which is in parallel to the output voltage at an output of the power converter;
• wherein the method comprises
• determining whether the input voltage is greater or smaller than a pre-determined voltage threshold;
• operating the first switcher stage to transfer electrical power from the input of the power converter to the output of the power converter, during a first time period when the input voltage is greater than the pre-determined voltage threshold;
• and
• operating the second switcher stage to transfer electrical power from the reservoir capacitor to the output of the power converter, during a second time period when the input voltage is smaller than the pre-determined voltage threshold.