Conclusion T8 Tube

 In order to test the operation of the protection circuit , we use a 38Ω resistor box instead of a   MR16  decimal LED string , the purpose is to simulate the design load current of the LED string voltage. By rapidly changing the load resistor from 38Ω to 1038Ω, you can simulate a open circuit failure .

 Shown in Figure 3 , such output current change ( green lines ) indicates a sudden change in load impedance . To compensate , TPS61170 output voltage ( yellow line ) up to the design load current is reached again . However, this change does not always been the case until it reaches its maximum duty cycle , the output voltage stabilized at about 16V clamping voltage.

Conclusion T8 Tube

We introduce you to configure a constant current LED driver boost converter provides an easy way to open-circuit protection . This circuit consists of a Zener diode and an additional resistor , whose output voltage is limited to a safe level , while in the open-circuit fault occurs when the load reduces the output current. In addition, this approach to the calculation of the load current caused some errors ,

 and to the efficiency during normal operation of the circuit is slightly reduced, but these effects are negligible . A boost converter is configured as a LED driver and add a 15V zener diode and a 1.2kΩ resistor for output protection . This will demonstrate proof of this protection circuit functionality. The demo demonstration circuit in the analog output load fault state performance in line with our expectations  LED Flexi