FUNCTIONAL DESCRIPTION

The L9907N is a power comparator with full-

bridge push-pull outputs, intended for driving a

DC motor in the headling adjustment system.

The basic function of the device is shown in the

input-output tranfer characteristic, Fig. 1.

the output voltage is negative (corresponds to

motor direction right), for increasing differential in-

put voltage, this status changes to the zero output

voltage (motor is actively braked), when the differ-

threshold. The output status remains in this condi-

tion as long as the differential input voltage re-

mains within the NEUTRAL ZONE. If the input

voltage increases above the positive NEUTRAL

positive (motor direction left).

Similar behaviour is obtained for decreasing the

input voltage. The output status transitions are

marked with the arrows showing the correspond-

ing direction of the output status variation. The

active braking mode is got with both outputs in

”HIGH” status

The above described behaviour assures high po-

sitioning precision, corresponding to the STOP

RANGE and high noise immunity in the adjusted

condition due to the NEUTRAL ZONE hysteresis

thresholds .

Both the above described thresholds are defined

drop over the input signal source resistances

necessary for the input current limitation during

resistors must be dimensioned so that in case of

a line transient the input current in the input pin,

clamped with the internal input protection diodes

do not increase over the specified absolute maxi-

mum value.

1.5V

0

1.5V

D95AT183A

Figure 2: Control to feedbacktransfer characteristic

D1

D2

PR

L9907N

INC

INF

GND

OUT C

OUT F

M

D95AT184

MODULE

Figure 3: Recommended Application Circuit Diagram with L9907N for tracking regulation

Note:

motor will not change its previous position.

L9907N

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