SVS-Vistek EXO Series, Manual

Page: 82 / 144

SVS-VISTEK
Feature-Set 82
7.3.4 PWM
Pulse width modulation
Description of the function used within the sequencer or implemented by
the pulseloop module
During Pulse Width Modulation, a duty cycle is modulated by a fixed
frequency square wave. This describes the ratio of ON to OFF as duty
factor or duty ratio.
Why PWM?
Many electrical components must be provided with a defined voltage.
Whether it’s because they do not work otherwise or because they have the
best performance at a certain voltage range (such as diodes or LEDs).
Diode characteristic
Since LEDs have a bounded workspace, the PWM ensures a variable
intensity of illumination at a constant voltage on the diodes.
In addition, the lifetime of a diode increases. The internal resistance is
ideal in this area. The diode gets time to cool down when operated with a
PWM in its workspace.
Implementation of PWM
Modulation frequency:
The basic frequency of the modulation is
defined by the cycle duration "T".
𝑇
𝑃𝑃𝑃
=
1
𝑓
𝑃𝑃𝑃
Cycle duration "T" is written into the registry by
multiple of the inverse of camera frequency.
(15 ns steps) Refer to:
Time unit of the
camera .
𝑇
𝑃𝑃𝑃
=
1
66, 6
�𝑀𝑀𝑀
∙ PWMMax[SeqSelector]
= 15 𝑛𝑠
∙ PWMMax[SeqSelector]