SLDS272 September 2024 DRV81620-Q1
ADVANCE INFORMATION
When EN_OLON bits are programmed with the value 1010b, the device starts a diagnosis loop where all auto-configurable (when used as high-side switches) channels are checked for Open Load at ON. First the internal logic checks all channels which are directly driven by the micro-controller and not configured to be driven by the internal PWM generator, then the internal logic checks all channels which are configured to be driven by the internal PWM generator.
Diagnosis sequence for channels driven directly by the micro-controller
First channel checked: channel 2. It is recommended that the channels are ON at least tON before enabling the diagnosis loop.
After a time tOLONSET + tSYNC the diagnosis for the first channel is completed (OLONx bit is updated)
The internal multiplexer is set to the next channel. After a time tOLONSW + tSYNC the diagnosis is completed (OLONx bit is updated) for the selected channel. This step is repeated for all remaining directly driven channels.
If one channel is OFF when the diagnosis is performed, the corresponding OLONx is set to 0b
Diagnosis sequence for channels driven by the internal PWM Generators
These channels are checked only after all channels directly driven by micro-controller are checked
Channels mapped to PWM Generator 0 are checked first
After a time tOLONSET the channel activation (switch ON) is the trigger event to perform Open Load at ON diagnosis for the first channel
After a time tONMAX + tOLONSW the diagnosis for the first channel is completed (OLONx bit is updated)
The internal multiplexer is set to the next channel. After a time tOLONSW the diagnosis is completed (OLONx bit is updated) for the currently selected channel. This step is repeated for all remaining PWM generator driven channels.
If the channel is in OFF state during the PWM period, the internal logic waits for the ON state to perform the diagnosis. After a time tONMAX + tOLONSW the diagnosis for that channel is completed.
The minimum ON time for a reliable diagnosis is > tONMAX + tOLONSW. If the ON time is < tONMAX + tOLONSW the corresponding OLONx is set to 0b.
When the loop finishes, EN_OLON bits are set back to 1111b (default value) and OLONx bits save the last diagnosis loop result. It is necessary to start another diagnosis loop to update the register content.