TLE 6209 R

Data Sheet, Version 3.0

8

2001-10-15

2.3.3

Direction and PWM

The power stages are controlled by the direct inputs DIR and PWM as given in Table 6

and further illustrated in Figure 2. The DIR input gives the direction of output current,

while the PWM input controls whether the current is increased or reduced. The SPI

control bit 2 sets the decay mode, i.e. determines what happens if PWM = L. In pulse-

width modulated applications, this control scheme allows to supply the PWM-signal

always through the same port, using less controller resources.

Figure 2

DIR/PWM Control with Slow- and Fast Decay

Table 6

Functional Truth Table

DIR

PWM

MODE

(Bit 2)

OUT1

OUT2

Comments

01

0

(slow decay)

H

L

Motor turns clockwise

0

0

H

H

Freewheel with slow decay

1

1

L

H

Motor turns counterclockwise

1

0

H

H

Freewheel with slow decay

01

1

(fast decay)

H

L

Motor turns clockwise

0

0

L

H

Fast decay

1

1

L

H

Motor turns counterclockwise

1

0

H

L

Fast decay

M

M

PWM = H

PWM = L

M

M

PWM = H

PWM = L

Slow Decay

Fast Decay