FAN8408D View Datasheet(PDF) - Fairchild Semiconductor

Part Name

Description

Manufacturer

FAN8408D

2 Phase Half Wave BLDC Motor Driver

Fairchild Semiconductor 

FAN8408D

Application Information

1. Lock Detection & Automatic Restart

Hall Input

Output

VLDCL

VLDCP

TOFF

TON

Motor lock

detected

Motor lock

Motor lock

cleared

Motor restart

FAN8408D features a lock detection and an automatic restart. The functions can be operated as follows.

1) When the hall signal stop switching, a motor can be locked.

2) The voltage, VLD on pin 3, is increasing until it reaches VLDCL.

3) If LD pin is connected to GND, the lockup protection is disabled.

4) While a motor is locked, the output repeats switching ON / OFF, but the other output is always OFF. The switching time can

be determined by an external capacitor on charging / discharging time of the capacitor, switching ON / OFF time can be

calculated as follows.

TON

=

-C----L----D------×----(---V----L----D-----C----L-----–------V-----L---D-----C-----P----)-

ILDC

TOFF

=

C-----L----D------×----(---V----L----D----C-----L-----–------V-----L---D-----C-----P-----)

ILDD

Where, The CLD is an external capacitor connected to pin 3, LD.

The VLDCL is the clamp voltage on pin 3, LD.

The VLDCP is the comparator voltage on pin 3, LD.

The ILDC is the charging current on pin 3, LD.

The ILDD is the dischaging current on pin 3, LD.

2. Thermal Shut Down

TSD On: All the outputs are off.(Typ. 175°C)

TSD Off: The circuit can be reactivated and begin to operate in a normal condition. (Typ. 150°C)

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