| 摘要 |
The invention provides a cost-effective driver circuit for an LED background lighting unit (BLU). For this purpose, a buck circuit with an upper transist or (T1) is provided. The buck transistor (1) is driven via two further transistors (Q1, Q2). The first transistor (Q1) is connected with its reference electrode to the positive terminal of a DC voltage source, with it s working electrode to the control electrode of the buck transistor (T1) and with its control electrode, via a capacitor (C3), to a signal contact, which can be driven externally. The second transistor (Q2) is connected with its reference electrode to ground, with its working electrode to the control electrode of the buck transistor (T1) and with its control electrode to a signal contact (K5), which can be driven externally. The buck transistor (T1 ) can be switched on via a corresponding gate signal at the terminal (K5) for the purpose of operating the light-emitting diodes (D5 to D10). Advantageously, cost-effective standard transistors (Q1, Q2) for operating voltages below 100 V can therefore be used for the switching controller.</SD OAB>
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