Single Coil Brushless DC Motor Drivers with Soft-Switching and PWM control

Version

：A.010

Page

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FD178A/FD178B/FD178C

Application Notes

The device can be operated with a wide supply voltage ranging from 2

to 6.5 Volts.

However, the design, specifications, and performance have been optimized for 5V

brushless dc motor applications.

The output driver node O1/O2 are in drive/sink state when V(HP) > V(HN) and vice

versa

The lock and auto-restart do not require an external capacitor for a timing counting

purpose. The driver will be shutdown approximately 1 second after the motor is lock

and the auto-restart is activated every one second until the lock is released.

Eliminating an external protection diode, a power polarity reverse circuit is integrated

on the chip.

A 1uF capacitor between VDD and GND as well as a 0.1uF between HP and HN are

strongly recommended for a reliable and noise immune operation.

The power dissipated by the chip varies with the supply voltage.

It is advisable to ensure the

power dissipation by the chip does not exceed the thermal requirement dictated by the package.

The maximum allowable power consumption can be calculated by the following equation:

)

/

)(

,

tan

Re

(

)

)(

(

)

)(max)(

(

)

)(

(

Watt

C

Ambient

to

Junction

ce

sis

Thermal

C

e

Temperatur

Ambient

Ta

C

e

Temperatur

Junction

Tj

Watt

n

Dissipatio

Power

Pd

o

JA

o

o

θ

−

=

The relationship between power dissipation and operating temperature can refer to the figure

below: