SLDS273A September 2024 – March 2025 DRV81080-Q1
PRODUCTION DATA
The device compares each channel VOUT with VOSM and sets the corresponding OSMx bits accordingly. The bits are updated every time OSM register is read.
A diagnosis current IOL in parallel to the power switch can be enabled by programming the IOLx bit, which can be used for Open Load at OFF detection. Each channel has dedicated diagnosis current source. If the diagnosis current IOL is enabled or if the channel changes state (ON → OFF or OFF → ON) waiting a time tOSM for a reliable diagnosis is necessary. Enabling IOL current sources increases the current consumption of the device. Even if an Open Load is detected, the channel is not latched OFF.
See Figure 7-15 for a timing overview (the values of IOLx refer to a channel in normal operation properly connected to the load).
Output Status Monitor diagnostic is available when VM = VM_NOR and VDD ≥ VDD_UVLO.
Due to the fact that Output Status Monitor checks the voltage level at the outputs in real time, for Open Load in OFF diagnostic synchronizing the reading of OSM register with the OFF state of the channels is necessary.
The following figure shows how Output Status Monitor is implemented at concept level.
In Standard Diagnosis the bit OLOFF represents the OR combination of all OSMx bits for all channels in OFF state which have the corresponding current source IOL activated.
When the DISOL bit is 1b, open load detection is disabled by disabling all the IOL current sources.