STK672-430A-E Sanyo Semicon Device, STK672-430A-E Datasheet - Page 13

• Manufacturer Part Number: STK672-430A-E
• Description: 2-phase Stepping Motor Driver
• Manufacturer: Sanyo Semicon Device

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2. Overcurrent Detection and Overheat Detection Functions of the STK672-430A-E and 440A-E
Each detection function operates using a latch system and turns output off. Because a RESET signal is required to
restore output operations, once the power supply, V DD , is turned off, you must either again apply power on reset with
V DD ON or apply a RESETB=High→Low→High signal.
[Overcurrent detection]
This hybrid IC is equipped with a function for detecting overcurrent that arises when the motor burns out or when there
is a short between the motor terminals.
Overcurrent detection occurs at 3.4A typ with the STK672-430A-E and at 5.0A typ for the STK672-440A-E.
Overcurrent detection begins after an interval of no detection (a dead time of 1.25μs typ) during the initial ringing part
during PWM operations. The no detection interval is a period of time where overcurrent is not detected even if the
current exceeds I OH .
[Overheat detection]
Rather than directly detecting the temperature of the semiconductor device, overheat detection detects the temperature
of the aluminum substrate (144°C typ).
Within the allowed operating range recommended in the specification manual, if a heat sink attached for the purpose of
reducing the operating substrate temperature, Tc, comes loose, the semiconductor can operate without breaking.
However, we cannot guarantee operations without breaking in the case of operations other than those recommended,
such as operations at a current exceeding I OH max that occurs before overcurrent detection is activated.
Set motor
current,
I OH
Normal operation
Current when motor terminals are shorted
No detection interval
(1.25 μ s typ)
PWM period
STK672-430A-E
Operation when motor pins are shorted
MOSFET all OFF
1.25 μ s typ
Overcurrent detection
I OH max
No.A1127-13/21
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