527
Motor driver ICs BA6840BFS / BA6840BFP-Y / BA6840BFP / BA6842BFS
Circuit operation
(1) Hall input output
The 3-phase Hall signal is amplified in the hall amplifiers
and sent to the matrix section, where the signal is further
amplified and combined. After the signal is converted to
a current in the amplitude control circuit, the current 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. 5.
(2) Torque control pin
The R
NF-pin current depends on the torque control input
voltage (EC) as shown in Fig. 6.
(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 transis-
tors are off) when the voltage is 1.5V or less.
(4) Power ground pin (R
NF pin)
The R
NF pin is the output stage ground pin. Connect a re-
sistor (0.5Ω recommended) between this pin and the
ground to monitor the output current.
(5) Phase compensation pin (C
NF pin)
Connect and adjust a capacitor between this pin and the
ground if the output tends to oscillate.
