lb11610p Sanyo Semiconductor Corporation, lb11610p Datasheet - Page 14

• Manufacturer Part Number: lb11610p
• Description: Three-phase Brushless Motor Driver
• Manufacturer: Sanyo Semiconductor Corporation

• Speed Control Circuit - Supplementary Documentation
The IC internal operation consists of creating a pulse signal from the FG signal edges as shown in the figure below,
and generating a pulse width waveform determined by the RC time constant in a one-shot multivibrator circuit.
The IC then integrates this pulse width waveform to create the IC control voltage (DC voltage) output.
Since the pulse width can be changed with the RC time constant, the slope of the VCTL - speed graph can be changed.
However, since pulses determined by the RC time constant are used, sample-to-sample variations in the RC
components will appear as speed control errors.
RC pin
Edge pulse
One-shot
multivibrat
or output
• Notes on the FVREF Pin
FG
Set the FVREF pin to the ground level to set the speed control diagram origin to 0% = 0 rpm. (See application
circuit 1.)
Input a voltage to the FVREF pin to shift the origin of the speed control diagram in the X direction from 0% = 0
rpm. (See application circuit 2)
Provide inputs such as those shown in application circuit 3 to shift the origin of the speed control diagram in the Y
direction from 0% = 0 rpm.
TRC(s) = 1.1RC
LB11610P
Slope due to
the RC time
constant
No.A0345-14/18