lv8735v ON Semiconductor, lv8735v Datasheet - Page 22

• Manufacturer Part Number: lv8735v
• Description: Bi-cmos Lsi Pwm Constant-current Control Stepping Motor Driver
• Manufacturer: ON Semiconductor

(3) Auto reset type
(4) Unusual condition warning output pins (EMO, MONI)
(5) Timer latch time (Tcem)
Overheating protection function
The overheating protection circuit is built into, and the output is turned off when junction temperature Tj exceeds
180°C, and the abnormal state warning output is turned on at the same time. The value of hysteresis and when it falls,
the temperature drives the output again (automatic restoration).
The overheating protection circuit doesn't secure protection and the destruction prevention of the set because it
becomes operation by the area where ratings Tjmax=150°C of the junction temperature was exceeded.
In the automatic reset mode, when the output current exceeds the detection current level, the output waveform
changes to the switching waveform.
As with the latch system, when the output short-circuited state is detected, the short-circuit protection circuit is
activated. When the operation of the short-circuit detection circuit exceeds the timer latch time (Tcem) described later,
the output is changed over to the standby mode and is reset to the ON mode again in 2ms (typ). In this event, if the
overcurrent mode still continues, the switching mode described above is repeated until the overcurrent mode is
canceled.
The LV8731V is provided with the EMO pin which notifies the CPU of an unusual condition if the protection circuit
operates by detecting an unusual condition of the IC. This pin is of the open-drain output type and when an unusual
condition is detected, the EMO output is placed in the ON (EMO = Low) state.
In the DC motor driver mode (DM = High), the MONI pin also functions as a warning output pin.
The functions of the EMO pin and MONI pin change as shown below depending on the state of the DM pin.
Furthermore, the EMO (MONI) pin is placed in the ON state when one of the following conditions occurs.
The time taken for the output to be set to OFF when the output has been short-circuited can be set using capacitor
Ccem, connected between the CEM pin and GND. The value of capacitor Ccem is determined by the formula given
below.
Timer latch : Tcem
Unusual condition
Channel 1 short-circuit detected
Channel 2 short-circuit detected
Overheating condition detected
1. Shorting-to-power, shorting-to-ground, or shorting-to-load occurs at the output pin and the output short-circuit
2. The IC junction temperature rises and the thermal protection circuit is activated.
protection circuit is activated.
When the DM is low (STM mode) :
When the DM is high (DCM) mode) :
TSD = 180°C (typ)
ΔTSD = 40°C (typ)
Tcem ≈ Ccem × Vtcem/Icem [sec]
EMO : Unusual condition warning output pin
MONI : Excitation initial position detection monitoring
EMO : Channel 1 warning output pin
MONI : Channel 2 warning output pin
Vtcem : Comparator threshold voltage, typ 1V
Icem : CEM pin charge current, typ 10μA
EMO
ON
ON
ON
DM = L (STM mode)
LV8735V
MONI
-
-
-
EMO
DM = H (DCM mode)
ON
ON
-
MONI
ON
ON
-
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