LB11847 Datasheet, PDF (14/16 Pages) Sanyo Semicon Device – PWM Current Control Type Stepping Motor Driver

LB11847
4. Simultaneous ON prevention function
This IC incorporates a circuit to prevent feedthrough current when phase switching. For reference, the output ON and
OFF delay times at PHASE and ENABLE switching are given below.
Reference data * typical value
PHASE switching
(Low -> High)
PHASE switching
(High -> Low)
ENABLE switching
ON delay time
OFF delay time
ON delay time
OFF delay time
ON delay time
OFF delay time
Sink side
1.9 µs
0.8 µs
1.4 µs
0.9 µs
2.15 µs
1.2 µs
Source side
2.2 µs
1.8 µs
1.7 µs
1.35 µs
2.75 µs
5.8 µs
5. Noise canceler
This IC has a noise canceling function to prevent malfunction due to noise spikes generated when switching ON. The
noise cancel time t_n is determined by internal resistance of the CR pin and the constant of the externally connected CR
components. The constant also determines the switching OFF time.
Figure 1 shows the internal configuration at the CR pin, and Figure 2 shows the CR pin constant setting range.
Equation when logic voltage V_CC = 5 V
CR pin voltage E1 = V_CC • R/(R1+R2+R) [V]
Noise cancel time t_{n =..} (R1+R2) • C • 1n {(E1-1.5)/(E1-4.0)} [s]
Switching OFF time t_off =.. –R • C • 1n (1.5/E1) [s]
Internal resistance at CR pin : R1 = 1 kΩ, R2 = 300Ω (typ.)
*The CR constant setting range in Figure 2 on page 15 is given for reference. It applies to a switching OFF time in the
range from 8 to 100 µs. The switching time can also be made higher than 100 µs. However, a capacitor value of more
than several thousand pF will result in longer noise canceling time, which can cause the output current to become higher
than the set current. The longer switching OFF time results in higher output current ripple, causing a drop in average
current and rotation efficiency. When keeping the switching OFF time within 100 µs, it is recommended to stay within
the CR constant range shown in Figure 2.
Internal configuration at CR pin
VCC line
One-shot multi-blanking
time circuit
CR pin
E1
R1 1 kΩ
R2
300Ω
C:470 pF
R:15 kΩ
Figure 1
A12543
No. 6183-14/16