ba6222.pdf

Motor driver ICs

Reversible motor driver

BA6222

The BA6222 is a reversible-motor driver with a maximum output current of 2.2A. Two logic inputs allow four output mo-

des: forward, reverse, idling, and braking. The motor revolving speed can be set arbitrarily by controlling the voltage

applied to the motor.

Applications

VCRs

Features

1) Large output current. (I OMax. = 2.2A)

2) Built-in thermal shutdown circuit.

3) Output voltage can be adjusted arbitrarily with the

output voltage setting pin. Because the pin has a gain

of 11.4dB, a high output voltage can be set with a low

input voltage.

4) Small standby circuit current.

Block diagram

Equivalent circuit for pins 5 and 6

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Motor driver ICs

BA6222

Input / output truth table

Absolute maximum ratings (Ta = 25

Electrical characteristics (unless otherwise noted, Ta = 25

C, V CC = 12V)

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Motor driver ICs

BA6222

Application example

V ofs

where V ofs is the error voltage, which varies with the out-

put current and the chip temperature. The output voltage

is about four times the voltage at pin 4.

The V 4 -value can be classified into three ranges accord-

ing to the output state :

A : V OH is at or near 0V

B : V OH is four times the gain

C : V OH -value is saturated

An oscillation may occur if a circuit having an output im-

pedance of more than a few hundred ohms is connected

to pin 4. In this case, connect a capacitor of at least

3300pF between pin 4 and GND.

(2) Thermal shutdown circuit

The thermal shutdown circuit turns off the driver output

if the chip temperature rises to about 150

(4) The quality of these products have been carefully

checked; however, use of the products with applied volt-

ages, operating temperatures, or other parameters that

exceed the absolute maximum rating given may result in

the damage of the IC and the product it is used in. If the

IC is damaged, the short mode and open modes cannot

be specified, so if the IC is to be used in applications

where parameters may exceed the absolute maximum

ratings, then be sure to incorporate fuses, or other physi-

cal safety measures.

(5) 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.

(6) 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.

(7) 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.

(8) 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 will be used.

(9) 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.

C. The shut-

down signal is not latched.

(3) Make sure that pin voltages will not exceed the sup-

ply voltage by more than 0.3V or will not become less

than the GND pin voltage by more than 0.3V.

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Operation notes

(1) Output voltage control pin (pin 4)

The voltage at pin 4 is related to the HIGH output voltage

(V OH ) as follows :

V OH = 4

V 4

Motor driver ICs

BA6222

(10) ASO

Make sure that the output current and supply voltage do

not exceed the ASO values.

(11) Precautions for input mode switching

To ensure reliability, it is recommended that the mode

switching for the motor pass once through the open

mode.

(12) In-rush current

There are no circuits built into these ICs that prevent in-

rush currents. Therefore, it is recommended to place a

current limiting resistor or other physical countermea-

sure.

(13) Factors regarding the thermal, power supply, and

motor conditions

If the potential of the output pin sways greatly and goes

below the potential of ground, the operation of the IC may

malfunction or be adversely affected. In such a case,

place a diode between the output and ground, or other

measure, to prevent this.

C 1 : Power supply filter capacitor. Place as near as pos-

sible to pin 1.

C 2 , C 3 : Capacitors to prevent both output transistors

being turned on at the same time.

C 4 : Surge voltage absorbing capacitor

C 5 : Oscillation preventing capacitor. An oscillation may

occur if a circuit having an output impedance of

more than a few hundred ohms is connected to pin

4. In this case, connect a capacitor of at least

3300pF.

R : Resistor used for reducing collector loss and lim-

iting the short-circuit current. A resistance range of

4.7

is recommended.

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Motor driver ICs

BA6222

Electrical characteristic curves

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