Rainbow Electronics BA6209N - Manual (Page 6)

391
Motor driver ICs BA6209 / BA6209N
F
Operation notes
(1) Resistor dividing IC power consumption
To reduce power dissipated in the IC, a resistance (about
3
X
10
Ω
) must always be connected between V
CC
and the
power supply pin of the driver circuit. If V
CC2
is connected
to V
CC
with no resistor, the IC can be damaged by over-
current when operated at the voltage range close to the
maximum operating voltage.
(2)
Control signal waveform
The rise and fall times of signals applied to the control
pins should be 5ms or less. Longer times can cause er-
ratic operation of the internal logic circuits and may result
in damage to the driver circuits.
For example, if the supply voltage for the external control
circuit comes up after the supply voltage of the IC, the ris-
ing edge of the control signal slowly follows the rise of the
external supply voltage. This could result in erratic opera-
tion or damage to the IC due to excess currents.
(3) IC ground voltage
To provide separation between the circuit elements with-
in the IC, the GND pin of the IC must always be held at
a lower potential than the other pins.
If the potential of the GND pin is allowed to rise above that
of other pins (such as the control input pins), separation
between the internal circuit elements could break down,
resulting in erratic operation or internal damage.
For example, a resistor may be connected between GND
(pin 1) and the ground as shown in Fig. 19, when detect-
ing and controlling the motor operating current. In this
case, the potential of pin 1 would be above the ground po-
tential by an amount equal to the voltage drop across the
resistor. Therefore, dropping the input pin potential to the
ground potential would have the effect of applying a neg-
ative voltage to the input pin.
This should be avoided by detecting the motor operating
current in a way shown in Fig. 20.
(4) Input pins
Voltage should never be applied to the input pins when
the V
CC
voltage is not applied to the IC. Similarly, when
V
CC
is applied, the voltage on each input pin should be
less than V
CC
and within the guaranteed range for the
electrical characteristics.
(5)
Back-rush voltage
Depending on the ambient conditions, environment, or
motor characteristics, the back-rush voltage may fluctu-
ate. Be sure to confirm that the back-rush voltage will not
adversely affect the operation of the IC.
(6)
Large current line
Large currents are carried by the motor power supply and
motor ground for these ICs.
Therefore, the layout of the pattern of the PC board and
the constants of certain parameters for external compo-
nents, such as the capacitor between the power supply
and ground, may cause this large output current to flow
back to the input pins, resulting in output oscillation or
other malfunctions. To prevent this, make sure that the
PC board layout and external circuit constants cause no
problems with the characteristics of these ICs.
(7)
Power dissipation
The power dissipation will fluctuate depending on the
mounting conditions of the IC and the ambient environ-
ment. Make sure to carefully check the thermal design of
the application where these ICs sill be used.
(8)
Power consumption
The power consumption by the IC varies widely with the
power supply voltage and the output current. Give full
consideration to the power dissipation rating and the
thermal resistance data and transient thermal resistance
data, to provide a thermal design so that none of the rat-
ings for the IC are exceeded.