SLDS272 September 2024 DRV81620-Q1
ADVANCE INFORMATION
The device compares each channel VDS with VOSM (for auto-configurable channels used in low-side switch configuration), VOUT_S with VOSM (for auto-configurable channels used in high-side switch configuration), VOUT with VOSM (for high-side channels) and sets the corresponding OSMx bits accordingly. The bits are updated every time OSM register is read.
VDS < VOSM → OSMx = 1b (low-side switch configuration)
VOUT_S > VOSM → OSMx = 1b (auto-configurable channels used as high-side)
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 its dedicated diagnosis current source. If the diagnosis current IOL is enabled or if the channel changes state (ON → OFF or OFF → ON) it is necessary to wait a time tOSM for a reliable diagnosis. 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 7-16 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 it is necessary to synchronize the reading of OSM register with the OFF state of the channels.
The following figures show 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.