L6386E STMicroelectronics, L6386E Datasheet - Page 8

• Manufacturer Part Number: L6386E
• Description: IC DRIVER HI/LO SIDE HV 14-DIP
• Manufacturer: STMicroelectronics
• Type: High Side/Low Sider

Specifications of L6386E

• Configuration: High and Low Side, Independent
• Input Type: Non-Inverting
• Delay Time: 110ns
• Current - Peak: 400mA
• Number Of Configurations: 1
• Number Of Outputs: 2
• High Side Voltage - Max (bootstrap): 600V
• Voltage - Supply: 17V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Through Hole
• Package / Case: 14-DIP (0.300", 7.62mm)
• Product: H-Bridge Drivers
• Rise Time: 50 ns
• Fall Time: 30 ns
• Maximum Power Dissipation: 750 mW
• Maximum Operating Temperature: + 125 C
• Mounting Style: Through Hole
• Bridge Type: Half Bridge
• Minimum Operating Temperature: - 45 C
• Number Of Drivers: 2
• For Use With: 497-5492 - EVAL BOARD FOR L6384/L6385/L6386
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-6215-5

Bootstrap driver
4
4.1
8/18
Bootstrap driver
A bootstrap circuitry is needed to supply the high voltage section. This function is normally
accomplished by a high voltage fast recovery diode
integrated structure replaces the external diode. It is realized by a high voltage DMOS,
driven synchronously with the low side driver (LVG), with in series a diode, as shown in
Figure 4
diode connected in series to the DMOS has been added to avoid undesirable turn on of it.
C
To choose the proper C
capacitor. This capacitor C
The ratio between the capacitors C
It has to be:
e.g.: if Q
300 mV.
If HVG has to be supplied for a long time, the C
the leakage losses.
e.g.: HVG steady state consumption is lower than 200 μA, so if HVG T
to supply 1 μC to C
The internal bootstrap driver gives great advantages: the external fast recovery diode can
be avoided (it usually has great leakage current).
This structure can work only if V
LVG is on. The charging time (T
fulfilled and it has to be long enough to charge the capacitor.
The bootstrap driver introduces a voltage drop due to the DMOS R
Ω). At low frequency this drop can be neglected. Anyway increasing the frequency it must be
taken in to account.
The following equation is useful to compute the drop on the bootstrap DMOS:
where Q
bootstrap DMOS, and T
BOOT
gate
gate
b. An internal charge pump
selection and charging
is 30 nC and V
is the gate charge of the external power MOS, R
EXT
. This charge on a 1 μF capacitor means a voltage drop of 1 V.
BOOT
charge
V
drop
EXT
gate
value the external MOS can be seen as an equivalent
is the charging time of the bootstrap capacitor.
=
Doc ID 13989 Rev 2
is related to the MOS total gate charge:
is 10 V, C
charge
OUT
I
ch
EXT
arg
is close to GND (or lower) and in the meanwhile the
(Figure 4
) of the C
e
R
and C
C
C
dson
EXT
EXT
BOOT
is 3 nF. With C
→
BOOT
=
>>>C
BOOT
b) provides the DMOS driving voltage. The
V
Q
-------------- -
V
BOOT
drop
gate
gate
EXT
is proportional to the cyclical voltage loss.
is the time in which both conditions are
(Figure 4
selection has to take into account also
=
------------------ - R
T
Q
ch
gate
BOOT
arg
DSon
e
a). In the L6386E a patented
dson
= 100 nF the drop would be
is the on resistance of the
DSon
ON
(typical value: 125
is 5 ms, C
BOOT
L6386E
has