No. 6185-8/9

LB1988N

Continued from preceding page.

Pin No.

Symbol

Voltage

Function

Equivalent circuit diagram

Drum motor driver output.

Lowest potential of the drum motor driver output

transistor.

Constant-current control is implemented by detecting

this voltage.

The current limiter also functions by detecting this

voltage.

16

UOUT

20

µF

3.9

Ω

3.9

Ω

16

18

17

22

20

23

24

30 k

Ω

30 k

Ω

10 k

Ω

VCC

200

Ω

23

24

22

19

200

Ω

200

Ω

2 k

Ω

16 17 18

10 k

Ω

1 k

Ω

5

µF

15

µF

15

µF

26

25

-VF

100

300

Ω

27

17

VOUT

18

WOUT

20

RF

Internal reference voltage and power supply for the

drum motor driver output block and coil waveform

detection circuit.

21

VCC

8 to 13.8 V

Motor coil midpoint input.

This voltage is used as the reference voltage in coil

voltage waveform detection.

Coil waveform detection comparator inputs.

These are connected to each of the phase outputs

though internal 10-k

Ω resistors.

Triangular waveform generator capacitor connection.

The triangular waveform generated using this pin is

used to implement soft switching for the coil output

waveforms.

The value of the capacitor connected between this

pin and ground in the VCO circuit determines the

operating frequency range and the minimum

operating frequency.

19

MCOM

22

UIN

23

VIN

24

WIN

25

C1

26

C2

27

CX

Continued on next page.