AN2590

Test results

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Test results

The evaluation results include the ballast system efficiency and the dimming characteristics

and performance of the power factor of the reference design board in addition to more

typical waveforms for evaluation boards.

The efficiency at full load in operating input voltage was higher than 80%, see Figure 12.

Figure 12.

Full load efficiency vs. AC line input

The triac turn on time per half cycle relates to the power dissipation of the lamp. The system

the range of Ton is 10 ms to 0ms corresponding to the firing angle 0° to 180°. But under real

conditions the range of Ton is about 9 ms to 2 ms, see Figure 13.

Figure 13.

Triac turn-on time vs. power dissipation to the lamp

Figure 14 shows the input voltage and current at maximum turn-on time of the triac. A glitch

(circled on the waveform) always exists at each half cycle of the input voltage. A current

spike (circled on the waveform) occurs at each half cycle when line voltage reaches the

peak. Although it is not good for the power factor, it is suitable for this application as it

ensures that the voltage on C1 is not higher than the peak of the input voltage.