BA6811 [ROHM]
Fan motor driver IC; 风扇马达驱动IC
| 型号： | BA6811 |
| 厂家： | 
ROHM |
| 描述： | Fan motor driver IC |
| 文件： | 总6页 (文件大小：91K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Motor driver ICs
Fan motor driver IC
BA6811F / BA6813F
The BA6811F and BA6813F are 2-phase, half-wave motor drivers suited for 12V fan motors. Built-in lock detection and
automatic restart mechanisms protect motors. Compact SOP8 (BA6811F/BA6813F) packages reduce the number of
external components required.
FApplications
2-phase fan motors
FFeatures
1) Built-in power transistors.
4) Alarm output pin. (BA6811F)
2) Lock detection and automatic restart mechanisms.
3) Built-in thermal shutdown circuit.
5) Hall signal output pin. (BA6813F)
6) Built-in reverse current protection diode.
FAbsolute maximum ratings (Ta = 25_C)
FRecommended operating conditions (Ta = 25_C)
712
Motor driver ICs
BA6811F / BA6813F
FBlock diagram
FPin descriptions
FHall input / output truth table
713
Motor driver ICs
BA6811F / BA6813F
FInput / output equivalent circuits
FElectrical characteristics (unless otherwise noted, Ta = 25_C, VCC = 12V)
714
Motor driver ICs
BA6811F / BA6813F
FCircuit operation
The BA6811F and BA6813F have motor lock detection
and automatic restart circuits. The timing of lock detec-
tion and automatic restart is determined by the external
capacitorconnected to the LD pin. The charge time of the
external capacitor is given by :
(Typical value)
where
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),
(0.76V),
(2.9µA),
(0.52µA),
C S (VLDCL*VLDCP)
TON (Charge time)=
ILDC
C is the capacitance of the LD-pin external capacitor.
For C=1µF, for example, the charge (output ON) and dis-
charge (output OFF) times are 0.40s and 2.25s, respec-
tively.
C S (VLDCL*VLDCP)
TOFF (Discharge time)=
ILDD
The timing chart for an occasion of motor locking is
shown in Fig. 1.
715
Motor driver ICs
BA6811F / BA6813F
FApplication example
FOperation notes
(1) Thermal shutdown circuit
(2) Power consumption
The IC has a built-in thermal shutdown circuit. The is a
temperature difference of 25_C (typical) between the
temperatures at which the circuit is activated and deacti-
vated.
Power consumed in the IC can be calculated from the fol-
lowing equation :
PC=PC1)PC2)PC3
PC1 is power consumed by the circuit current.
PC1=VCC ICC
PC2 is the output current consumption.
PC2=VOL IO
VOL is the LOW level output voltage of output pins
1 and 2, and IO is the sink current of pins 1 and 2.
PC3 is power consumed by the AL and HO pins.
PC3=VALL IAL)VHOL IHO / 2
where
VALL is the AL-pin LOW level voltage,
IAL is the AL-pin sink current,
VHOL is the HO-pin LOW level voltage,
IHO is the HO-pin sink current.
Make sure that your application does not exceed the al-
lowable power dissipation of the IC.
Thecircuitisactivatedatthetemperatureofabout175_C
(typical), so that all outputs are turned OFF. Normal op-
eration resumes when the circuit is deactivated.
716
Motor driver ICs
BA6811F / BA6813F
VCC
(3)Hall amplifier input voltage
Hall current is given by :
R1)R2)RH
where RH is the Hall device impedance.
The R1 and R2 resistances must be set so as to maintain
the Hall amplifier input bias voltage within the range of 0V
to (VCC*2.8V) including the signal amplitude.
The Hall device may be affected by power supply noise
due to the PCB conductor pattern. If you have this prob-
lem, insert a capacitor C1 as shown in Fig. 5.
If the conductor lines from the Hall device output termi-
nalsto the Hall inputs of the IC are particularly long, noise
can be picked up and fed into the inputs. If you have this
problem, insert a capacitor C2 as shown in Fig. 5. Note
that the Hall inputs have no hysteresis in this IC.
FExternal dimensions (Units: mm)
717
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