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Revision 0.7

14 - 42

with additional features

with photosensor

AS3636

Preliminary Datasheet, Confidential - D e ta i l e d D e s c r i p t i o n

IGBT Driver

The IGBT Driver shown in Figure 10 has an internal glitch filter to filter out short spikes with a length of up to

14). The actual IGBT driver consists of three current source. One is connected to VOUTBOOST to driver the

IGBT_GATE high. The two other current sources drive the IGBT_GATE low, where the falling edge is divided into two

sections:

1. IGBT_rise_and_fall_speed control the edge from VOUTBOOST to VOUTBOOST/2

2. IGBT_fall_speed2zero control the remaining part from VOUTBOOST/2 to GND.

Figure 10. IGBT Driver internal circuit

If the STROBE pulse is longer than 2ms, a timeout timer fault is raised and the strobe pulse is stopped - see Xenon

charger and strobe timeout fault (TOF) on page 19.

IGBT Pulse Timing adjustment

The IGBT pulse timing can be extended by a programmable duration to allow the fine adjustment of the light output

from the Xenon tube during flash especially for light pulses with very short time typically used for pre-flash pulses (typ-

ically about 5µs). This adjustment can be performed on a module by module basis thus accurately trimming the light

output energy over production for pre-flash pulses.

The internal circuit for this pulse adjustment is shown in Figure 11:

















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AS3636