17XSF500 Datasheet, PDF (42/70 Pages) Freescale Semiconductor, Inc – Penta 17 mOhm High Side Switch

OLLED TRIG 1
ONoff & PWM
h son _1
En _OLLed_1
OUT_1
Note: OLLED TRIG bit is reset after the detection
FF
100 sec
100 sec
VP_BAW_T-0R.7-05.75
OUT_h igh
Analog Co mparator output
check
Ch ec k
Precision ~ 9600 ns
TimeOut = 2.0 msec
1 : olled detected
0 : no olled detected
Figure 25. OpenLoad in ON State for LED in Fully ON Operation
The OLLED TRIG bit is reset after the detection.
To delatch the diagnosis:
• a read command of the corresponding channel status register #2… #6 must be performed
A false “open” result could be reported in the OLON bit:
• for high duty cycles, the PWM off-time becomes too short
• for capacitive load, the output voltage slope becomes too slow
6.1.5.1.3 OpenLoad in OFF State
An OpenLoad in off state detection is provided individually for each power output (OUT1… OUT5).
The detection is enabled individually for each channel by the OLOFF EN bits inside the OpenLoad control register #13-1.
When the corresponding OLOFF EN is
• low (logic[0]), the diagnosis mode is disabled (default status)
• high (logic[1]), the diagnosis mode is started for t_OLOFF. It is not possible to restart any OLOFF or disable the
diagnosis mode during active OLOFF state
This detection can be activated independently for each power output (OUT1… OUT5). But when it is activated, it is always
activated synchronously for all selected outputs (with positive edge of CS\).
When the detection is started, the corresponding output channel is turned on with a fixed overcurrent threshold of I_OLOFF
threshold.
When this over current threshold:
• is reached within the detection timeout t_OLOFF, the output is turned off and the OLOFF EN bit is reset. No OCLOx
and no OLOFFx will be reported
• is not reached within the detection timeout t_OLOFF, the output is turned off after t_OLOFF and the OLOFF EN bit is
reset. The OLOFFx will be reported
The overcurrent behavior, as commanded by the overcurrent control settings (NO OCHIx, OCHI ODx, SHORTOCHIx, OCLOx,
ACM ENx), is not be affected by applying the OLOFF ENx bit. The same is true for the output current feedback and the current
sense synchronization.
The detection result is reported:
• in the corresponding QSFx bit in the quick status register #1
• in the global OpenLoad flag OLF (register #1… #7)
• in the OLOFF bit of the corresponding channel status register #2… #6
MC17XSF500
42
Analog Integrated Circuit Device Data
Freescale Semiconductor