606

Motor driver ICs

BA6458FP-Y

FCircuit operation

(1)

The 3-phase Hall signal is amplified in the hall am-

plifiers and sent to the matrix section, where the signal is

further amplified and combined. After the signal is con-

verted to a current in the amplitude control circuit, the cur-

rent is supplied to the output driver, which then provides

a motor drive current. The phases of the Hall input signal,

output voltage, and output current are shown in Fig. 1.

(2)

Torque control pin

The output current can be controlled by adjusting the

voltage applied to the torque control pin (pin 9).

(3)

Start / stop pin

The motor is in the run mode when the pin input voltage

is 3.5V or more and in the idle mode (all output transistors

are off) when the voltage is 1.2V or less.

(4)

sistor (0.5

Ω recommended) between this pin and the

ground to monitor the output current.

(5)

Torque limit pin (TL pin)

The output current can be limited by applying a voltage

to the torque limit pin. Control is provided so that this pin

there is an offset in the TL-pin voltage.

(6)

put tends to oscillate.

(7)

Amplifiers 1 and 2

Amplifiers 1 and 2 have an open loop gain of about 70dB

(typical). The input terminals are biased internally to

2.45V (typical).

(8)

Hysteresis amplifiers

The hysteresis amplifiers have a hysteresis width of

±120mV (typical). The input terminals are biased inter-

nally.