391

Motor driver ICs

BA6209 / BA6209N

FOperation notes

(1)

Resistor dividing IC power consumption

To reduce power dissipated in the IC, a resistance (about

3

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

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.