AN2531
Over voltage protection
15/40
6.2 Type
of
solutions
shows possible types of over voltage protection. The first solution proposes
a Transil™ or a Zener diode connected between each channel of the LED driver and
ground. Unidirectional Transils with break down voltage lower than 16 V such as the SMAJ
Transil family (refer to
, point
) can be used.
The second solution proposes to use a standard diode or Schottky diode as a freewheeling
diode. Diodes are connected between the LED supply voltage (DC bus) and driver's channel
and so limit the voltage on the channels.
The third solution is the most cost effective and uses only a single Zener diode which
protects all channels. It can be used only if the connection between the LED driver and LED
cathodes is a quite short and if the connection between LED supply voltage and anodes is
long. This protection limits over voltage peaks on LED anodes.
Figure 9.
Possible over voltage protections
AM00292
SPI
STP04CM596
Control
and
logic
part
4 V at 3 A
Temperature sensor
Full color pixel
Maximum output
voltage 16 V
Lp
Lp
Lp
Lp
Lp
3
D
2
1
Transil
Zener
diode
4
Zener
diode
