LB1668 Datasheet, PDF (7/8 Pages) Sanyo Semicon Device – Two-Phase Unipolar Drive Brushless Motor Drivers

LB1668, 1668M
Automatic Recovery Circuit C-pin Voltage
VTH1 ⁶
5
4
VTH2
3
2
1
0
0123
t1
Rotation Output on
1
2
Lock
456
t2
Output off
789
t3
Output
on
10 11 12 13 14 15 16 17
t (s)
Output off
Rotation
Lock released
Automatic return circuit C pin voltage
1) While the blades are turning, the capacitor is charged with a current of about 3μA (typical), and C is discharged by
pulses that correspond to the motor speed.
2) When the blades lock, the capacitor is no longer discharged, and the voltage across the capacitor increases. The
output is turned off when that voltage reaches 0.8 × VIN.
3) When the output is turned off, the capacitor is discharged at about 0.44μA (typical). When the capacitor voltage
falls under VTH2, if the lock state is not yet cleared the capacitor continues discharging until VTH1. (Note that the
output is turned on at this time.)
These operations, i.e. items 2. and 3., are repeated with a ton:toff ratio of about 1 : 6 to protect the motor.
4) If the lock is cleared at the point the capacitor voltage reaches VTH2, motor rotation is started by turning the output
on.
VO(sat) – IO
2.0
ASO
2
1.6
1.2
VIN ^{= 6.7V}
0.8
0.4
0
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
Output current, IO – mA
VIN – ICC
10
300μs
1.0
400μs
500μs
7
5
3
2
Ta = 80°C
0.1 ^{Single pulse}
2
3
5 7 ₁₀
2
3
5
Collector/emitter voltage, VCE – V
7 ₁₀₀
8
IN+ = L
6
4
2
0
0
2
4
6
8
10
12
Input current, ICC – mA
No.4944-7/8