BA6427F [ROHM]
Single-phase full-wave motor driver; 单相全波电机驱动器
| 型号： | BA6427F |
| 厂家： | 
ROHM |
| 描述： | Single-phase full-wave motor driver |
| 文件： | 总5页 (文件大小：78K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Motor driver ICs
Single-phase full-wave motor driver
BA6427F
TheBA6427Fisasingle-phasefull-wavemotordriverforfanmotors. Byusingthisdriver, asingle-phase, full-wavemotor
driver circuit can be built with fewer components than a circuit using operational amplifiers. Lock detection and automatic
restart mechanisms, which are required for fan motors, are alsobuiltin. Arotational-speedsensingoutputpinisprovided
for Ho output.
FApplications
Single-phase, full-wave fan motors
FFeatures
1) Equipped with lock detection and rotational-speed
sensing functions.
3) Automatic restart when the motor lock is undone.
2) Compact SOP-8 package reduces the number of ex-
ternal components for a reduced mounting area.
FAbsolute maximum ratings (Ta = 25_C)
FRecommended operating conditions
763
Motor driver ICs
BA6427F
FBlock diagram
FPin descriptions
FTruth table
764
Motor driver ICs
BA6427F
FElectrical characteristics (unless otherwise noted, Ta = 25_C, VCC = 5V)
765
Motor driver ICs
BA6427F
FLock detection
FOperation notes
The automatic restart circuit detects a motor lock condi-
tion and automatically turns off the output power. When
the lock condition is cleared, the IC automatically restarts
and allow the motor to run.
(1) Thermal shutdown circuit
The IC has a built-in thermal shutdown circuit. There is
a degree of hysteresis in the TSD circuit.
In the BA6427F, automatic restart is performed as fol-
lows.
A motor lock condition is detected when the Hall signal
stopsswitching. TheoutputisOFFwhentheLDpinisbe-
ing charged.
(1) The HO pin outputs a signal synchronized with the
Hall signal.
(2) The HO pin is an open collector output.
The time required for the external capacitor at the LD pin
to charge or discharge when the motor is locked varies
with the capacitor size. The charge and discharge times
are obtained by:
Thecircuitisactivatedatthetemperatureofabout175_C
(typical), so that all outputs are turned OFF. The circuit is
deactivated when the temperature drops to about
150_C, and normal operation resumes. (With the typical
values, there is a hysteresis of 25_C.)
C (VLDCL – VLDCP)
(2) Current consumption
TON (charge time) =
ILDC
The power dissipated by the IC varies widely with the
supply voltage and the output current. Make sure that
your application does not exceed the allowable power
dissipation of the IC package.
C (VLDCL – VLDCP)
TOFF (discharge time) =
ILDD
)
*
C is the capacitance of the external capacitor connected
to the LD pin,
(3) Hall input pins (H , H )
VLDCL is the LD pin clamp voltage
VLDCP is the LD pin comparator voltage
ILDC is the LD pin charge current
ILDD is the LD pin discharge current
(1.93V Typ.),
(0.76V Typ.),
(2.9µA Typ.),
(0.48µA Typ.).
For C = 0.47µF, for example, the charge and discharge
times are 0.19 s (output ON) and 1.15 s (output OFF),
respectively.
The timing of the LD pin is shown in Fig.1.
(1) The values of the Hall device bias resistors (see the
block diagram) must be set so as to maintain the Hall am-
plifier input bias voltage within the range of 0V to VCC-2V,
including the signal amplitude. It is recommended that
the same value be used for both resistors so that the Hall
device output signal centered around VCC / 2 is input to
the IC.
(2) Be careful of the input signal for the Hall inputs of this
IC have no hysteresis.
(4) ASO
Make sure that the output current will not exceed the ab-
solute maximum rating or the ASO value.
(5) Ground pin potential
Be sure to keep the GND potential lower than the poten-
tials of the other pins.
766
Motor driver ICs
BA6427F
FElectrical characteristic curves
FExternal dimensions (Units: mm)
767
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