MIC5014 Micrel Semiconductor, MIC5014 Datasheet - Page 9

• Manufacturer Part Number: MIC5014
• Description: Low-Cost High- or Low-Side MOSFET Driver
• Manufacturer: Micrel Semiconductor

MIC5014/5015
High Side Driver With Load Protection (Figure 12) Al-
though the MIC5014/15 devices are reverse battery pro-
tected, the load and power FET are not, in a typical high side
configuration. In the event of a reverse battery condition, the
internal body diode of the power FET will be forward biased.
This allows the reversed supply access to the load.
1997
Push-Pull Driver With No Cross-Conduction (Figure 13)
As the turn-off time of the MIC5014/15 devices is much faster
than the turn-on time, a simple push-pull driver with no cross
conduction can be made using one MIC5014 and one
MIC5015. The same control signal is applied to both inputs;
the MIC5014 turns on with the positive signal, and the
MIC5015 turns on when it swings low.
This scheme works with no additional components as the
relative time difference between the rise and fall times of the
MIC5014 is large. However, this does mean that there is
Control Input
Figure 12: High Side Driver WIth Load Protection
OFF
ON
Control Input
10µF
10µF
Figure 13: Push-Pull Driver
1
2
3
4
V+
Input
Source
Gnd
12V
MIC5014
1
2
3
4
1
2
3
4
V+
Input
Source
Gnd
V+
Input
Source
Gnd
MIC5014
MIC5015
5-145
Gate
NC
NC
NC
The addition of a Schottky diode between the supply and the
FET eliminates this problem. The MBR2035CT was chosen
as it can withstand 20A continuous and 150A peak,
and should survive the rigors of an automotive environment.
The two diodes are paralleled to reduce switch loss (forward
voltage drop).
considerable deadtime (time when neither driver is turned on).
If this circuit is used to drive an inductive load, catch diodes
must be used on each half to provide an alternate path for the
kickback current that will flow during this deadtime.
This circuit is also a simple half H-bridge which can be driven
with a PWM signal on the input for SMPS or motor drive
applications in which high switching frequencies are not
desired.
Gate
Gate
8
7
6
5
NC
NC
NC
NC
NC
NC
8
7
6
5
8
7
6
5
12V
12V
IRF540
IRFZ40
IRFZ40
MBR2035CT
V
OUT
Micrel
5