High efficiency inductor-less off-line LED driver

A driver circuit to control a solid state lighting, the driver circuit comprising:

• a first power converter converting a varying input voltage at an input of the power converter into an output voltage at an output of the power converter supplying the output voltage to the solid state lighting, comprising;
• one or more capacitors;
• a plurality of switches coupling said one or more capacitors with one another, with the input and/or with the output of the power converter according to a plurality of configurations;
• and
• a control unit operating the power converter in a plurality of operational modes providing a corresponding plurality of different conversion ratios between the input voltage and the output voltage of the power converter, wherein a first operational mode of said plurality of operational modes comprises a first phase, during which the one or more capacitors are arranged in a first configuration from said plurality of configurations, and a second phase, during which the one or more capacitors are arranged in a different second configuration from the plurality of configurations.

A power converter to convert a varying input voltage at an input into an output voltage at an output;

• wherein the power converter is configured to supply the output voltage to a solid state lighting device in series with a current source;
• the power converter comprising:
• an input port to receive a rectified input voltage;
• a first switch, wherein a first terminal of the switch is connected to the input port and a second terminal of the first switch is connected to a first output port;
• a first capacitor, wherein a first terminal is connected to the input port and a second terminal is connected to an anode of a first diode to a cathode of a second diode and to a first terminal of a second capacitor;
• said first diode, wherein a cathode is connected to the first output port;
• said second diode wherein an anode is connected to a second output port;
• said second capacitor, wherein a second terminal is connected to ground;
• a second switch wherein a first terminal is connected to the second output port and a second terminal is connected to ground;
• and
• said first and second output ports wherein a load is connected between both output ports.

A power converter to convert a varying input voltage at an input into an output voltage at an output;

• wherein the power converter is configured to supply the output voltage to a solid state lighting device in series with a current source;
• the power converter comprising:
• an input port to receive a rectified input voltage;
• a first switch, wherein a first terminal of the switch is connected to the input port and a second terminal of the first switch is connected to a first terminal of a second switch, to a first terminal of a third switch, and to a first terminal of a first capacitor;
• said second switch wherein a second terminal is connected to an output port of the power converter;
• said third switch wherein a second terminal of the second switch is connected to a first terminal of a second capacitor and to a second terminal of a fourth switch;
• said first capacitor, wherein a second terminal is connected to a first terminal of the fourth switch and to a first terminal of a fifth switch;
• said fourth switch;
• said fifth switch wherein a second terminal of the fifth switch is connected to a second terminal of the second capacitor;
• said second capacitor wherein a second terminal is connected to an anode of a first diode and to a cathode of a second diode;
• said first diode, wherein a cathode is connected to the output port;
• said second diode wherein an anode is connected to ground;
• and
• said output port wherein a load is connected between the output port and ground.

A method for converting a varying input voltage into an output voltage for a solid state lighting device in series with a current source;

• the method comprising:
• (1) providing a SSL, a driver circuit comprising a control unit, a means to couple and decouple a plurality of components, a load current source, and a capacitor
• (2) measuring the input voltage;
• (3) selecting an operational mode based on the measured input voltage, wherein the selected operational mode provides a conversion ratio between the input voltage and the output voltage and wherein the selected operational mode comprises a first phase and a second phase;
• (4) configuring one or more capacitors of the capacitor bank according to a first configuration by said means to couple and decouple a plurality of components during the first phase of the operational mode;
• (5) configuring one or more capacitors of the capacitor bank according to a second configuration by said means to couple and decouple a plurality of components during the second phase of the operational mode;
• (6) implement the selected operational mode by alternating repeatedly between the first phase of step (4) and the second phase of step (5) at the commutation cycle rate until the end of an execution cycle;
• and
• (7) go back to step (2) after the end of the execution cycle.