LB11975 Datasheet, PDF (8/12 Pages) Sanyo Semicon Device – High-Speed CD-ROM Spindle Motor Driver IC

LB11975
Continued from preceding page.
Pin No. Pin
11
FC
Pin voltage
Function
Control loop frequency characteristics
correction
Closed loop oscillation in the current
control system can be stopped by
connecting a capacitor between this pin
and ground.
10
PWM
PWM oscillator capacitor connection
Equivalent circuit
11
500Ω
500Ω
65kΩ
10
500Ω
VCC1
2kΩ
Control reference voltage input
13
V_CREF
0 V to
V_CC1 – 1.5 V ^{The control start voltage is determined by}
this voltage.
14
V_CTL
3, 4
6, 7
30, 31
1, 2
35, 36
OUT3
GND2
OUT2
OUT1
28
RF
Speed control voltage input
This IC implements a voltage control
system in which VC > V_CREF means
14
0 V to
forward rotation and VC < V_CREF means
V_CC1 – 1.5 V slow foward rotation.
(This IC includes reverse rotation
prevention circuit, so reverse rotation will
not occur.)
W phase output
Ground for the output transistors
500Ω
VCC1
V phase output
U phase output
Upper side npn transistor collector
(shared by all three phases)
Connect a resistor between V_CC3 and the
RF pin for current detection. The fixed
current control system and the current
limiter operate by detecting this voltage.
2kΩ
2kΩ
VCC1
500Ω
13
VCC3
28
VCC2
1234
35 36
6 7 30 31
VCC1
12
PH
Peak hold circuit capacitor connection.
Connect a capacitor to this pin to smooth
the voltage detected by the resistor RF.
300Ω
12
11kΩ
No. 6497-8/12