Datasheet

Device description L6730 - L6730B
30/52 Doc ID 11938 Rev 3
5.14 Bootstrap anti-discharging system
This built-in anti-discharging system keeps the voltage going across the bootstrap capacitor
from going below 3.3 V. An internal comparator senses the voltage across the external
bootstrap capacitor and helps to keep it charged, eventually turning on the low-side
MOSFET for approximately 200 ns. If the bootstrap capacitor is not charged up enough, the
high-side MOSFET cannot be effectively turned on and it will present a higher R
DS(on)
. In
some cases, the OCP can be also triggered. There are up to two conditions during which
the bootstrap capacitor can be discharged:
● fan power supply failure, and
● no sink at zero current operation.
Figure 25. 14 V -> 0.5 V@820 kHz, 5 A
50ns