STK672-432A-E Datasheet, PDF (13/21 Pages) Sanyo Semicon Device – Thick-Film Hybrid IC 2-phase Stepping Motor Driver

STK672-432A-E
2. Overcurrent Detection and Overheat Detection Functions
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, VDD, is turned off, you must either again apply power on reset with
VDDON 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 STK672-432A-E.
Set motor
current,
IOH
Current when motor terminals are shorted
PWM period
MOSFET all OFF
Overcurrent detection
IOHmax
No detection interval
(1.25μs typ)
Normal operation
1.25μs typ
Operation when motor pins are shorted
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 IOH.
[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 IOH max that occurs before overcurrent detection is activated.
No.A1586-13/21