KA3012D

9

3. DRIVER

• The gain of pre-op. Amplifier can be changed by manipulating amp input resistor or feedback resistor.

• The level shift produces the current due to the difference between the pre amp output signal and the arbitrary reference

(bias) signal. (The current produced as +

∆I and −∆I is fed into the driver buffer. (CH1/CH4)

The current produced as +2

∆I and −2∆I is fed into the driver buffer. (CH2/CH3)

• Driver buffer drives the power TR of the output stage according to the state of the input signal.

• The output stage is the BTL driver and the motor is rotating in forward direction by operating TR Q1 and TR Q4.On the

other hand, if TR Q2 and TR Q3 is operating, the motor is rotating in reverse direction.

4. CONNECT A BY-PASS CAPACITOR, 0.1

µµµµF BETWEEN THE SUPPLY VOLTAGE SOURCE.

5. RADIATION FIN IS CONNECTING TO THE INTERNAL GND OF THE PACKAGE.

CONNECT THE FIN TO THE EXTERNAL GND.

+

−

+

−

+

−

10k

BIAS

(6 Pin)

10k

AMP

−∆I

+

∆I

Buffer

Buffer

Q1

Q3

M

Q2

Q4

−∆V+∆V

CH-O

(1, 14,

16, 27 Pin)

CH-O

(2, 13,

17, 26 Pin)

+

−

Level

shift

AMP-I (+)

(5, 10, 20, 23 Pin)

AMP-I (

−)

(4, 11, 19, 24 Pin)

AMP-O

(3, 12, 18, 25 Pin)

Pre-amp

A

V

20 log

4V

IN

V

IN

------------

12 dB

() (CH1/CH4)

==

A

V

20 log

4V

IN

V

IN

------------

18 dB

() (CH1/CH4)

==

7

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