LED System Driver ICs

ICLS6x Series

Functional Description

Data Sheet

19

Version 1.0, 2011-05-19

3.5.1

Leading Edge Blanking

Each time when the integrated internal CoolMOS™ is switched on, a leading edge spike is generated due to the

primary-side capacitances and secondary-side rectifier reverse recovery time. This spike can cause the gate drive

to switch off unintentionally. To avoid premature termination of the switching pulse, this spike is blanked out with

Figure 11

.

Figure 11

Leading edge blanking

3.5.2

Propagation Delay Compensation

In the case of overcurrent detection, switch-off of the integrated internal CoolMOS™ is delayed due to the

ratio of dI/dt of the peak current (see Figure 12).

Figure 12

Peak current overshooting

The overshoot of Signal2 is greater than that of Signal1 due to the steeper rising waveform. This change in the

slope varies according to the AC input voltage. A Propagation Delay Compensation circuit is integrated to limit the

overshoot dependency on dI/dt of the rising primary current. This means that the propagation delay between the

compensated over temperature within a wide range.

t

t

Signal1

Signal2