BA6950FS [ROHM]
Reversible motor driver; 可逆电机驱动器
| 型号： | BA6950FS |
| 厂家： | 
ROHM |
| 描述： | Reversible motor driver |
| 文件： | 总6页 (文件大小：101K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Motor driver ICs
Reversible motor driver
BA6950FS
The BA6950FS is a reversible-motor driver suited for brush motors. Two logic inputs allow four output modes: forward,
reverse, stop (standby), and brake. The rotational speed of motor can be set arbitrarily by changing the voltage applied
to the motor with control pins. The IC can also drive a motor at a constant speed by using a built-in current feedback
amplifier.
FApplications
VCRs, audio equipment
FFeatures
1) Twologicinputsallowfouroutputmodes:forward, re-
verse, stop (standby), and brake.
3) Built-in current feedback amplifier allows constant
motor speed.
2) Motor speed variable with voltage control signals.
4) Control gain can be set arbitrarily by using external
resistors.
5) Built-in thermal shutdown circuit.
FAbsolute maximum ratings (Ta = 25_C)
FRecommended operating conditions (Ta = 25_C)
484
Motor driver ICs
BA6950FS
FBlock diagram
FPin descriptions
485
Motor driver ICs
BA6950FS
FInput/output circuit (resistances, in Ω, are typical values)
(1) R and F inputs (pins 5 and 10)
(3) Motor output (pins 6, 7, 8, and 9)
(2) CTL amplifier (pins 2 and 3)
486
Motor driver ICs
BA6950FS
FElectrical characteristics (unless otherwise noted, Ta = 25_C, VCC = 4.8V, VB = 4.8V)
FCircuit operation
(1) Input section (FIN, RIN)
(3) Output high level voltage
Control signals are input from these pins. Current flows
from M2 to M1 (forward mode) when FIN is HIGH and RIN
is LOW, and from M1 to M2 (reverse mode) when RIN is
HIGH and FIN is LOW. Putting FIN and RIN both HIGH re-
sults in the brake mode in which the high-side output
transistor is turned off to shut down the motor driving cur-
rent and the low-side output transistor is turned ON toab-
sorb the counter-electromotive force of the motor, so that
a brake is put on the motor. When FIN and RIN are both
LOW, both M1 and M2 are left open and the motor stops.
Input/output truth table
Values of current, voltage, and HIGH level output voltage
can be set as follows by using external resistors (refer to
the application circuit of Fig. 4).
S I16 pin (IRT1)
1
I16 pin (IRT1) = V2 pin/R1
S I15 pin (IRT2)
I15 pin (IRT2) = I8 pin R5/R4
S V16 pin (VRT1)
V16 pin = R3 (I16 pin)I15 pin))R2 I16 pin
S S S
2
S S S
3
S S S
S V7, 9 pin (M1, M2 voltage; high-side voltage)
V7, 9 pin = 4 V16 pin (Typ.)
4
S S S
(4) Current feedback amplifier
The pin-8 current is increased when the motor rotational
speed is reduced by loading, and the current feedback
amplifier increases the pin-15 current according to equa-
2
tion . Because the pin-16 voltage then increases ac-
3
cording to equation , the HIGH level output voltage
4
(2) Output section (M1, M2)
also increases according to equation . In this way, the
Two logic inputs control the motor by changing the status
of bridge-configured transistors.
rotational speed is kept constant by increasing the volt-
age applied to the motor.
487
Motor driver ICs
BA6950FS
Aplicaioexample
FOperation notes
(1) Thermal shutdown circuit
current of up to a few hundred milliamperes can flow be-
tween the motor power supply (pin 6) and RNF (pin 8).
Depending on the application, this large output current
may flow back to input pins, resulting in output oscillation
or other malfunctions. Make sure that your design does
not allow a common impedance between the large cur-
rent output lines and the input section. Suppress the
power supply impedance to low levels, otherwise output
oscillation may occur.
The thermal shutdown (TSD) circuit turns off all driver
outputs when the IC junction temperature rises above
175_C (Typ.). The temperature difference between the
activation and deactivation settings is about 20_C.
STemperature setting of TSD
(4) Package power
The power dissipated by the IC varies widely with the
supply voltage and the output current. Give full consider-
ation to the package power dissipation rating when set-
ting the supply voltage and the output current.
(5) The input pins (pins 5 and 10) have temperature-
dependent characteristics. Take the temperature effect
into consideration when using the IC.
(2) Control logic and control signal input pins
Voltage should never be applied to the control logic input
pins (pins 5 and 10) or the control signal input pin (pin 2)
when the VCC voltage is not applied to the IC. Similarly,
the voltage on each input pin should not exceed any ap-
plied VCC voltage.
(6) To eliminate motor noise, connect a capacitor be-
tween M1 (pin 7) and GND and between M2 (pin 9) and
GND.
(3) PCB arrangement
Whenchangingtherotationaldirectionofamotor, alarge
488
Motor driver ICs
BA6950FS
FElectrical characteristic curves
FExternal dimensions (Units: mm)
489
相关型号：
©2020 ICPDF网 联系我们和版权申明