Datasheet

DocID023278 Rev 4 31/75
L6480 Functional description
75
active (if supplied). The thermal shutdown condition only expires when the temperature
goes below T
j(SD)ON
.
The thermal condition of the device is shown by TH_STATUS bits in the STATUS register
(Table 10).
6.13 Reset and standby
The device can be reset and put into Standby mode through the STBY/RESET pin. When it
is forced low, all the MOSFETs are turned off (High Z state), the charge pump is stopped,
the SPI interface and control logic are disabled and the internal
V
REG
voltage regulator
maximum output current is limited; as a result, the L6480 heavily reduces the power
consumption. At the same time the register values are reset to their default and all the
protection functions are disabled. The STBY
/RESET input must be forced low at least for
t
STBY,min
in order to ensure the complete switch to Standby mode.
On exiting Standby mode, as well as for IC power-up, a delay must be given before applying
a new command to allow proper oscillator and charge pump startup. Actual delay could vary
according to the values of the charge pump external components.
On exiting Standby mode all the MOSFETs are off and the HiZ flag is high.
The registers can be reset to the default values without putting the device into Standby
mode through the ResetDevice command (Section 9.2.14 on page 69).
6.14 External switch (SW pin)
The SW input is internally pulled up to V
DD
and detects if the pin is open or connected to
ground (see Figure 13).
The SW_F bit of the STATUS register indicates if the switch is open (‘0’) or closed (‘1’)
(Section 9.1.24 on page 59); the bit value is refreshed at every system clock cycle (125 ns).
The SW_EVN flag of the STATUS register is raised when a switch turn-on event (SW input
falling edge) is detected (Section 9.1.24 on page 59). A GetStatus command releases the
SW_EVN flag (Section 9.2.20 on page 71).
Table 10. Thermal protection summarizing table
State Set condition Release condition Description TH_STATUS
Normal Normal operation state 00
Warning T
j > Tj(WRN)Set
T
j > Tj(WRN)Rel
Temperature warning: operation is not
limited
01
Bridge shutdown T
j > Tj(OFF)Set
T
j > Tj(OFF)Rel
High temperature protection: the
MOSFETs are turned off and the gate
drivers are disabled
10
Device shutdown T
j > Tj(SD)Set
T
j > Tj(SD)Rel
Overtemperature protection: the
MOSFETs are turned off, the gate drivers
are disabled, the internal V
CC
voltage
regulator is disabled, the current capability
of the internal V
REG
voltage regulator is
limited, and the charge pump is disabled
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