AMIS30512 ON Semiconductor, AMIS30512 Datasheet - Page 18

• Manufacturer Part Number: AMIS30512
• Description: Micro-stepping Motor Driver
• Manufacturer: ON Semiconductor

Thermal Warning and Shutdown
warning bit <TW> is set (Table 27: SPI Status Register 0).
If junction temperature increases above thermal shutdown
level, then the circuit goes in “thermal shutdown” mode,
<TSD> bit is set and all driver transistors are disabled (high
impedance) (Table 29: SPI Status Register 2). The
conditions to reset flag <TSD> is to be at a temperature
lower than T
using any SPI read command.
Over−Current Detection
current in each activated output stage. If the load current
exceeds the over−current detection threshold, then the
over−current flag is set and the drivers are switched off to
reduce the power dissipation and to protect the integrated
circuit. Each driver transistor has an individual detection bit
in the Table 28: SPI Status Register 1 and Table 29: SPI
Status Register 2 (<OVCXij> and <OVCYij>). Error
When junction temperature rises above T
The over−current detection circuit monitors the load
SLA−pin
PWMsh
Icoil = 0
V
SLAT
COIL
TW
V
PWMsh
Icoil = 0
COIL
SLAT = 1 ≥ SLA−pin is “transparent” during
V
Crossing. SLA−pin is updated “real−time”.
and to clear the <TSD> flag by reading it
BEMF
sampling @ Coil Current Zero
div2
div4
Warning, Error Detection and Diagnostics Feedback
Ssh
Figure 13. Timing Diagram of SLA−pin
Csh
TW
, the thermal
Sh
last sample
is retained
http://onsemi.com
SLAT = 0 ≥ SLA−pin is not “transparent” during V
sampling @ Coil Current Zero Crossing. SLA−pin is
updated when leaving current−less state.
Ch
V
BEMF
18
SLAT
NOT (Icoil = 0)
previous output is kept at SLA pin
buf
condition is latched and the microcontroller needs to clean
the status bits to reactivate the drivers.
NOTE:
Open Coil Detection
percent duty cycle of the PWM regulator. If in a coil 100
percent duty cycle is detected for longer than t
then
(high−impedance) and an appropriate bit in the SPI status
register is set (<OPENX> or <OPENY>). (Table 27: SPI
Status Register 0).
Charge Pump Failure
low Rdson for all drivers, especially for low supply voltages.
If the supply voltage is too low or external components are
Open coil detection is based on the observation of 100
The charge pump is an important circuit that guarantees
the
Successive reading the SPI Status Registers 1 and 2 in
case of a short circuit condition, may lead to damage to
the drivers.
Changing the current over different current ranges might
lead to false over current triggering.
SLA−pin
related
driver
retain last sample
transistors
BEMF
t
t
are
OC
= 200 ms
disabled