Electronic ballast for operating at least one first cascade of LEDs and one second cascade of LEDs
First Claim
1. An electronic ballast for operating at least one first cascade of light emitting diodes and one second cascade of light emitting diodes, comprising:
- an input with a first input connection and a second input connection for coupling to an AC supply voltage;
a rectifier, which is coupled to the first input connection and the second input connection, wherein the rectifier has an output with a first output connection and a second output connection;
a first unit, which comprises the first cascade of light emitting diodes and a first storage capacitor, which is connected in parallel with the first cascade of light emitting diodes;
at least one second unit, which comprises at least the second cascade of light emitting diodes and a second storage capacitor, which is connected in parallel with the second cascade of light emitting diodes;
wherein the first unit is coupled to the first output connection, and the at least one second unit is coupled in series with the first unit, to be precise on the side of the first unit which is not coupled to the first output connection;
wherein the at least one second unit also comprises a diode, which is coupled in series with the parallel circuit comprising the second cascade of light emitting diodes and the second storage capacitor, to be precise on the side which faces the first unit;
wherein the electronic ballast further comprises;
a current controller with an actual value input for the current through the cascades of light emitting diodes and a setpoint value input,a setpoint value presetting apparatus for the current through the cascades of light emitting diodes, wherein the setpoint value presetting apparatus is designed to provide a setpoint value at the setpoint value input which is proportional to the voltage at the output of the rectifier;
a first actuating element, which is coupled in series with the at least one second unit, to be precise on that side of the at least one second unit which is remote from the first unit;
wherein the at least one second unit comprises a second actuating element, which is connected in parallel with the series circuit comprising the diode and the parallel circuit comprising the second cascade of light emitting diodes and the second storage capacitor,wherein the current controller comprises a drive output, wherein the drive output is coupled to the first actuating element and the at least one second actuating elementwherein the current controller comprises an operational amplifier with an inverting input, which represents the actual value input, a non-inverting input, which represents the setpoint value input, and an output, which represents the drive output, wherein a parallel circuit, comprising a first Zener diode and an ohmic resistor, is coupled between the drive output and the inverting input.
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Accused Products
Abstract
An electronic ballast may include: a rectifier; a first unit including a first cascade of LEDs and a first storage capacitor connected in parallel with the first cascade; a second unit including at least a second cascade of LEDs and a second storage capacitor connected in parallel with the second cascade; wherein the second unit includes a diode coupled in series with the parallel circuit including the second cascade; wherein the electronic ballast includes: a current controller with an actual value input and a setpoint value input, a setpoint value presetting apparatus for the current through the cascades, wherein the setpoint value presetting apparatus is designed to provide a setpoint value at the setpoint value input which is proportional to the voltage at the output of the rectifier; a first actuating element; wherein the controller includes a drive output coupled to the first actuating element and a second actuating element.
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Citations
9 Claims
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1. An electronic ballast for operating at least one first cascade of light emitting diodes and one second cascade of light emitting diodes, comprising:
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an input with a first input connection and a second input connection for coupling to an AC supply voltage; a rectifier, which is coupled to the first input connection and the second input connection, wherein the rectifier has an output with a first output connection and a second output connection; a first unit, which comprises the first cascade of light emitting diodes and a first storage capacitor, which is connected in parallel with the first cascade of light emitting diodes; at least one second unit, which comprises at least the second cascade of light emitting diodes and a second storage capacitor, which is connected in parallel with the second cascade of light emitting diodes; wherein the first unit is coupled to the first output connection, and the at least one second unit is coupled in series with the first unit, to be precise on the side of the first unit which is not coupled to the first output connection; wherein the at least one second unit also comprises a diode, which is coupled in series with the parallel circuit comprising the second cascade of light emitting diodes and the second storage capacitor, to be precise on the side which faces the first unit; wherein the electronic ballast further comprises; a current controller with an actual value input for the current through the cascades of light emitting diodes and a setpoint value input, a setpoint value presetting apparatus for the current through the cascades of light emitting diodes, wherein the setpoint value presetting apparatus is designed to provide a setpoint value at the setpoint value input which is proportional to the voltage at the output of the rectifier; a first actuating element, which is coupled in series with the at least one second unit, to be precise on that side of the at least one second unit which is remote from the first unit; wherein the at least one second unit comprises a second actuating element, which is connected in parallel with the series circuit comprising the diode and the parallel circuit comprising the second cascade of light emitting diodes and the second storage capacitor, wherein the current controller comprises a drive output, wherein the drive output is coupled to the first actuating element and the at least one second actuating element wherein the current controller comprises an operational amplifier with an inverting input, which represents the actual value input, a non-inverting input, which represents the setpoint value input, and an output, which represents the drive output, wherein a parallel circuit, comprising a first Zener diode and an ohmic resistor, is coupled between the drive output and the inverting input. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification