Rainbow Electronics BA6955N - Manual (Page 5)

BA6283N / BA6955N
Motor driver ICs
V V V CC V IR
V OF V OR
V IF V M
Fig.5
V CE : Sum of the high and low side output transistor voltage.
I O flows from High to Low Level output pins.
! ! ! ! Circuit operations
(1) Input section (F
IN
, R
IN
)
Control signals are input from these pins. Input circuit can be controlled with TTL or over voltage input.
Operation in each mode is show below.
Output current flows from OUT1 to OUT2 (forward mode) when F
IN
is High and R
IN
is Low, and from OUT2 to OUT1
(reverse mode) when R
IN
is Low and R
IN
is High. Putting F
IN
and R
IN
both High result in the brake mode. In this mode,
the high-side output transistor is turned off to shut down the motor driving current and the low-side output transistor is
turned on to absorb the counter-electromotive force of the motor. When F
IN
and R
IN
are both Low, both OUT1 and
OUT2 are left open and the motor stops. In this mode the power save circuit turn to active, and whole the IC circuit off
cause the circuit current to minimize.
Input / output truth table
F IN
H
L
H
L
R IN
L
H
H
L
OUT1
H
L
L
OPEN
OUT2
L
H
L
OPEN
Mode
Forward
Reverse
Brake
Standby
(2) Output section (OUT1, OUT2)
Two logic inputs control the motor by changing the status of the bridge-configured transistors.
(3) Power supply section (V
CC
, V
M
)
V
CC
is a logic Power supply terminal, and V
M
is a Motor Power supply terminal.
(4) Thermal shut down (TSD)
When the IC internal temperature rises by the accident motor locked, the thermal shut down circuit is activated and all
the outputs turn off with regardless of input mode. Then, the temperature fulls and the thermal shut down circuit is
disactirated, the output returns with regard of the input mode.
This circuit is activated when the IC junction temperature rises above 175
°C (Typ.) and disabled when it is 150°C
(Typ.).
(5) Power save circuit
When F
IN
and R
IN
are both Low, all the IC circuit turns off and it decrease the IC consumption current.