L6221C_03 datasheet(9/15 Pages) STMICROELECTRONICS

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Figure 19 : Driver for Solenoids up to 3A.

Some care must be taken to ensure that the collec-

tors are placed close together to avoid different cur-

rent partitioning at turn-off.

We suggest to put in parallel channel 1 and 4 and

channel 2 and 3 as shown in figure 19 for the similar

electrical characteristics of the logic section (turn-on

and turn-off delay time) and the power stages (col-

lector saturation voltage, free-wheeling diode for-

ward voltage).

APPLICATION INFORMATION

When inductive loads are driven by L6221C/CD, a

zener diode in series with the integral free-wheeling

diodes increases the voltage across which energy

stored in the load is discharged and therefore

speeds the current decay (fig. 18).

The zener has to be chosen in such a way that

VCLAMP is limited to 60V taking into account the

zener’s voltage changes due to: spread on VZ, tem-

perature changes, and the voltage drop due to oh-

mic resistance.

Moreover, the instantaneous power must be limited

in order to avoid the reverse second breakdown.

Figure 18.

L6221C

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