AN2334

Hardware implementation

19/22

The L9950 loads are shown in the following table:

The input signals INA and INB are directly interfaced with the microcontroller to select the

motor direction and the brake condition. The DIAGA/ENA or DIAGB/ENB, connected to the

I/O microcontroller and configured as input pull-up, enable the legs of the bridge. They also

provide a digital diagnostic signal. The CS pin allows monitoring the motor current by

delivering a current proportional to its value. The PWM, up to 20 KHz, allows control of the

motor speed in all possible conditions.

The reverse polarity protection MOSFET needs a zener diode and a resistor between gate

and source to protect against ISO pulses and for proper turn off in static reverse polarity.

In master node application, a LOW ohmic resistor must be connected externally between

LIN and battery to allow the maximum transmission rate.

Finally, all outputs need a 10nF capacitor to protect the module against 8 kV ESD events.

Figure 9.

Board Layout

Table 10.

L9950 Loads

L9950 Outputs

Load

OUT1

Common Mirror Motors

OUT2

X Mirror Motor

OUT3

Y Mirror Motor

OUT4

Lock Motor

OUT5

Lock Motor

OUT6

Mirror Fold Motor

OUT7

Exterior Light

OUT8

Footstep Light

OUT9

Safety Light

OUT10

Turn Indicator

OUT11

Defroster

Parallel Port

Connector

Gnd

+12

Lin

ICP

Connector

Window

A

Window

B

Up

Down

Wake Up

Reset

Enable

Parallel Port

Connector

Gnd

+12

Lin

ICP

Connector

Window

A

Window

B

Up

Down

Wake Up

Reset

Enable