ML4411 typical application circuit

PWM and linear current control: In order to facilitate speed control, ML4411
is equipped with two current control loops, linear and PWM. The motor current is
detected by the voltage drop on the sampling resistor. It is input from pin 12. The built-in transconductance amplifier amplifies
the difference between pin 12 J (SENSE) and pin 28 (CMD>, and its output modulates three N
channels. MOSFET switch. This is a linear control loop. The (SENSE) signal is also compared with the 27
-pin J (LIMIT) signal in the comparator. The comparator output is connected to a monostable
circuit , and the latter is connected to the 13-pin external capacitor Cc )s timing. These circuits form the PWM
current limiting circuit. The function of these two circuits is to control the motor current to
the smaller of (CMD) and (I.IMIT).
  (5) Braking control
  In order to brake the motor, first make pin 8 zero level, and then make
the BRAKE level of pin 26 drop. When the level drops below 1.4V, the internal comparator forces the three
N-channel MOSFETs to turn on to brake the motor .
    4Typical Application Figure 3-53 is an example of hard disk drive spindle control. Its
control signals come from the superior controller.