BA6950FS, BA6951FS
Technical Note
●External application components setting procedure
The relation between VCTL and the output high voltage is as follows.
· IRT1 = VCTL / R1
· IRT2 = IACT x R5 / R4
· VRT1 = R3 x ( IRT1 + IRT2 ) + R2 x IRT1
· VMX = 4 x VRT1
····· (1)
····· (2)
····· (3)
····· (4)
VCTL: Torque control voltage
IACT: Motor current
VM1, VM2: Output high voltage
VMX =
4 ( R2 + R3 )
R1
x VTCL +
4 R3 R5
R4
x IACT
····· (5)
To drive the motor by constant speed as follows.
RL + RON + R5 =
4 R3 R5
R4
····· (6)
RL: Motor coil impedance
RON: On resistance of the driver IC
R3, R4, and R5 are first set, and then R1 and R2 are set afterwards.
Parts
R1
R2 + R3
R4
R5
C1
C2
C3, C4
C5, C6
Default value
22kΩ
1kΩ + 1.5kΩ
560Ω
5.5Ω
33pF
0.1µF
0.1µF
1~100µF
Table 4 External components
Parameter
IRT1
VRT1
IRT2
VATC
VPCT
VPC
VM1, VM2
VCC, VB
Recommended condition
IRT1 < 1mA
VRT1 x 4 < VB
IRT2 < 1mA
VATC < 1V
Please confirm the motor
operation
●Interfaces
FIN
13.5k 10k
RIN
3.6k
10k
10k
24k
1k
VCTL
20k
1k
PCT
RC
1k
PC
Fig. 17 FIN, RIN
Fig.18 VCTL, RC, PCT
TL
1k
1k
RT1
1k
CS1
RT2
1k
CS2
1k
CS
Fig. 20 RT1, RT2
Fig.21 CS1, CS2
(BA6950FS)
Fig.22 CS, TL
(BA6951FS)
Fig.19 PC
VB
M1
M2
ACT
Fig.23 VB, ACT, M1,M2
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7/10
2011.05 - Rev.C