L6387 STMicroelectronics, L6387 Datasheet - Page 4

• Manufacturer Part Number: L6387
• Description: IC DRIVER HI/LO SIDE HV 8MINIDIP
• Manufacturer: STMicroelectronics
• Type: Low Side Driverr

Specifications of L6387

• 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: 8-DIP (0.300", 7.62mm)
• Rise Time: 50 ns
• Fall Time: 30 ns
• Supply Voltage (min): 8 V
• Supply Current: 220 mA
• Maximum Power Dissipation: 750 mW
• Maximum Operating Temperature: + 125 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: - 50 C
• Number Of Drivers: 2
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-5782; L6387

L6387
Figure 1. Typical Rise and Fall Times vs.
Input Logic
L6387 Input Logic is V
terlocking features is offered (see truth table be-
low) to avoid undesired simultaneous turn ON of
both Power Switches driven.
Table 1.
BOOTSTRAP DRIVER
A bootstrap circuitry is needed to supply the high
voltage section. This function is normally accom-
plished by a high voltage fast recovery diode (fig.
3a). In the L6387 a patented 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 fig. 3b
An internal charge pump (fig. 3b) provides the
DMOS driving voltage .
The diode connected in series to the DMOS has
been added to avoid undesirable turn on of it.
CBOOT selection and charging:
To choose the proper C
MOS can be seen as an equivalent capacitor.
This capacitor C
gate charge :
4/9
(nsec)
Input
Output
time
250
200
150
100
50
0
For both high and low side buffers @25˚C Tamb
0
Load Capacitance
1
HVG
LVG
HIN
LIN
EXT
2
is related to the MOS total
CC
BOOT
(17V) compatible. An in-
3
0
0
0
0
value the external
0
1
0
1
4
Tr
Tf
1
0
1
0
5
D99IN1054
C (nF)
1
1
0
0
3nF. With
leakage losses.
e.g.: HVG steady state consumption is lower than
200 A, so if HVG T
pacitor means a voltage drop of 1V.
The internal bootstrap driver gives great advan-
tages: the external fast recovery diode can be
avoided (it usually has great leakage current).
This structure can work only if V
GND (or lower) and in the meanwhile the LVG is
on. The charging time (T
Ohm). At low frequency this drop can be ne-
glected. Anyway
must be taken in to account.
The following equation is useful to compute the
Figure 2. Quiescent Current vs. Supply
The ratio between the capacitors C
is proportional to the cyclical voltage loss .
It has to be:
e.g.: if Q
300mV.
If HVG has to be supplied for a long time, the
C
supply 1 C to C
the time in which both conditions are fulfilled and
it has to be long enough to charge the capacitor.
The bootstrap driver introduces a voltage drop
due to
( A)
10
10
10
10
Iq
BOOT
4
3
2
0
selection has to take into account also the
the DMOS R
2
gate
Voltage
C
BOOT
4
is 30nC and V
C
EXT
BOOT
C
6
= 100nF the drop would be
increasing the frequency
EXT
. This charge on a 1 F ca-
ON
>>>C
8
DSON
is 5ms, C
charge
Q
V
10
gate
gate
EXT
gate
(typical value: 125
12
) of the C
is 10V, C
OUT
EXT
14
BOOT
and C
is close to
D99IN1055
16 V
BOOT
has to
EXT
BOOT
S
(V)
is
is
it