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LED Driver ICs Forum Discussions

User20729
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5 questions asked First question asked
Level 1
According to the datasheet of LITIX™ Basic/Basic+ devices the reverse protection should be integrated in the devices. So do we not need to place any external protection against the reverse voltage for LEDs connected to the IC output or to protect the IC itself?
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j_oehmen
Moderator
Moderator 10 replies posted 5 replies posted 10 questions asked
Moderator
LITIX Basic and Basic+ devices are reverse polarity protected:

* LITIX™ Basic down to -16V
* LITIX™ Basic+ down to -18V

This means that if we have a static pulse higher than -18V and we don’t have an external reverse polarity diode we could destroy the device.

For transient pulses we recommend a TVS diode ±36V, reverse polarity diode 36V and ceramic capacitor inline with the EMC report:

4889.attach

Note: The EMC test applies the surge pulse on a single device only. System-level behavior depends on number of components and filters present on the shared supply line. This usually relaxes the stress seen by a single device. Consequently the removal of a reverse diode can be assessed by the customer based on characterization results.

Another idea is an asymmetrical configuration, with two unidirectional suppressor diodes 15V and 26V and a ceramic capacitor. In this case you won’t need the reverse polarity diode, but an assessment on system-level is required.
4890.attach

See the corresponding datasheets at https://www.infineon.com/cms/en/product/power/lighting-ics/litix-automotive-led-driver-ic/litix-basi... .

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j_oehmen
Moderator
Moderator 10 replies posted 5 replies posted 10 questions asked
Moderator
LITIX Basic and Basic+ devices are reverse polarity protected:

* LITIX™ Basic down to -16V
* LITIX™ Basic+ down to -18V

This means that if we have a static pulse higher than -18V and we don’t have an external reverse polarity diode we could destroy the device.

For transient pulses we recommend a TVS diode ±36V, reverse polarity diode 36V and ceramic capacitor inline with the EMC report:

4889.attach

Note: The EMC test applies the surge pulse on a single device only. System-level behavior depends on number of components and filters present on the shared supply line. This usually relaxes the stress seen by a single device. Consequently the removal of a reverse diode can be assessed by the customer based on characterization results.

Another idea is an asymmetrical configuration, with two unidirectional suppressor diodes 15V and 26V and a ceramic capacitor. In this case you won’t need the reverse polarity diode, but an assessment on system-level is required.
4890.attach

See the corresponding datasheets at https://www.infineon.com/cms/en/product/power/lighting-ics/litix-automotive-led-driver-ic/litix-basi... .
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