Circuit arrangement for operating at least one light-emitting diode
First Claim
1. A circuit arrangement for operating at least one light-emitting diode (LED) in an electrical circuit at a service voltage (UB), which is greater than the forward voltage of the at least one light-emitting diode (LED) which is to be operated,wherein adjustment of a current flowing through the light-emitting diode (LED) is performed by means of pulse-width modulation of a first switching means (S1), which is switched between a first terminal of the service voltage (UB) and the light-emitting diode LED,wherein between the first terminal of the service voltage (UB) and the at least one light-emitting diode (LED) a first reactance formed by a first resistance (R1) and a first capacitor (C1) is arranged,characterized in thatthe at least one light-emitting diode (LED) is connected via a second reactance formed by a second resistance (R2) and a second capacitor (C2) to a second terminal of the service voltage,between the two connections of the at least one light-emitting diode (LED) and the two reactances (R1-C1, R2-C2) a full-wave rectifier diode bridge of four diodes (D1, D2, D3, D4) being switched, andat a tap between the first switching means (S1) and the at least one light-emitting diode (LED) a connection, switchable via a second switching means (S2), to the second terminal of the service voltage exists, the second switching means (S2) being operated in push-pull action to the first switching means (S1).
1 Assignment
0 Petitions
Accused Products
Abstract
A circuit arrangement is for operating at least one light-emitting diode LED in an electrical circuit at a service voltage greater than the forward voltage of the at least one light-emitting diode. The light-emitting diode is PWM-controlled. The circuit includes reactances that are connected in series at both connections of the light-emitting diode, an additional switching arrangement between the terminals, and a full-wave rectifier circuit, such that the circuit is protected against short-circuits on the service voltage and on ground while the LED can continue to be triggered.
-
Citations
6 Claims
-
1. A circuit arrangement for operating at least one light-emitting diode (LED) in an electrical circuit at a service voltage (UB), which is greater than the forward voltage of the at least one light-emitting diode (LED) which is to be operated,
wherein adjustment of a current flowing through the light-emitting diode (LED) is performed by means of pulse-width modulation of a first switching means (S1), which is switched between a first terminal of the service voltage (UB) and the light-emitting diode LED, wherein between the first terminal of the service voltage (UB) and the at least one light-emitting diode (LED) a first reactance formed by a first resistance (R1) and a first capacitor (C1) is arranged, characterized in that the at least one light-emitting diode (LED) is connected via a second reactance formed by a second resistance (R2) and a second capacitor (C2) to a second terminal of the service voltage, between the two connections of the at least one light-emitting diode (LED) and the two reactances (R1-C1, R2-C2) a full-wave rectifier diode bridge of four diodes (D1, D2, D3, D4) being switched, and at a tap between the first switching means (S1) and the at least one light-emitting diode (LED) a connection, switchable via a second switching means (S2), to the second terminal of the service voltage exists, the second switching means (S2) being operated in push-pull action to the first switching means (S1).
Specification