STMicroelectronics Fully integrated stepper motor driver mounting the L6472 in a high power PowerSO package EVAL6472PD EVAL6472PD Data Sheet
Product codes
EVAL6472PD
DocID022729 Rev 3
29/70
L6472
Functional description
70
Warning:
The overcurrent shutdown is a critical protection feature. It is
not recommended to disable it.
not recommended to disable it.
6.10 Undervoltage
lockout
(UVLO)
The L6472 provides motor supply UVLO protection. When the motor supply voltage falls
below the V
below the V
SthOff
threshold voltage, the STATUS register UVLO flag is forced low. When
a GetStatus command is sent to the IC, and the undervoltage condition expires, the UVLO
flag is released (see
flag is released (see
). The undervoltage
condition expires when the motor supply voltage goes over the V
SthOn
threshold voltage.
When the device is in the undervoltage condition, no motion command can be performed.
The UVLO flag is forced low by logic reset (power-up included) even if no UVLO condition is
present.
The UVLO flag is forced low by logic reset (power-up included) even if no UVLO condition is
present.
6.11
Thermal warning and thermal shutdown
An internal sensor allows the L6472 to detect when the device internal temperature exceeds
a thermal warning or an overtemperature threshold.
a thermal warning or an overtemperature threshold.
When the thermal warning threshold (T
j(WRN)
) is reached, the TH_WRN bit in the STATUS
register is forced low (see
) until the temperature decreases below T
j(WRN)
and a GetStatus command is sent to the IC (see
).
When the thermal shutdown threshold (T
j(OFF)
) is reached, the device goes into the thermal
shutdown condition: the TH_SD bit in the STATUS register is forced low, the power bridges
are disabled bridges in high-impedance state and the HiZ bit in the STATUS register is
raised (see
are disabled bridges in high-impedance state and the HiZ bit in the STATUS register is
raised (see
).
The thermal shutdown condition only expires when the temperature goes below the thermal
warning threshold (T
warning threshold (T
j(WRN)
).
On exiting the thermal shutdown condition, the bridges are still disabled (HiZ flag high);
whichever motion command makes the device exit from High Z state (HardStop and
SoftStop included).
whichever motion command makes the device exit from High Z state (HardStop and
SoftStop included).
6.12
Reset and standby
The device can be reset and put into standby mode through a dedicated pin. When the
STBY\RST pin is driven low, the bridges are left open (High Z state), the internal charge
pump is stopped, the SPI interface and control logic are disabled, and the internal 3 V
voltage regulator maximum output current is reduced to IREG,STBY; as a result, the L6472
heavily reduces the power consumption. At the same time the register values are reset to
default and all protection functions are disabled. STBY\RST input must be forced low at
least for t
STBY\RST pin is driven low, the bridges are left open (High Z state), the internal charge
pump is stopped, the SPI interface and control logic are disabled, and the internal 3 V
voltage regulator maximum output current is reduced to IREG,STBY; as a result, the L6472
heavily reduces the power consumption. At the same time the register values are reset to
default and all protection functions are disabled. STBY\RST 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 of up to t
logicwu
must be given
before applying a new command to allow proper oscillator and logic startup and a delay of
up to t
up to t
cpwu
must be given to allow the charge pump startup.