L6911E

Device description

13/34

Figure 4.

Soft start

5.4

Driver section

The driver capability on the high and low side drivers allows to use different types of power

The low-side mos driver is supplied directly by Vcc while the high-side driver is supplied by

the BOOT pin.

Adaptative dead time control is implemented to prevent cross-conduction and allow to use

many kinds of mosfets. The upper mos turn-on is avoided if the lower gate is over about

200mV while the lower mos turn-on is avoided if the PHASE pin is over about 500mV. The

upper mos is in any case turned-on after 200nS from the low side turn-off.

The peak current is shown for both the upper (Figure 5 on page 14) and the lowr (Figure 6

on page 14) driver at 5V and 12V. a 4nF capacitive load has been used in these

measurements.

Similary, for the upper driver, the source peak current is 1.3A @ Vboot-Vphase = 12V and

600mA @ Vboot-Vphase = 5V, and the sink peak current is 1.3A @ Vboot-Vphase = 12V

and 550mA @ Vboot-Vphase = 5V.

Vcc Turn-on threshold

Vin Turn-on threshold

0.5V

1V

Vcc

Vin

Vss

LGATE

Vout

to GND

Timing diagram