MIC5016_02 Datasheet, PDF (8/12 Pages) Micrel Semiconductor – Low-Cost Dual High- or Low-Side MOSFET Driver

MIC5016/5017
Micrel
Incandescent/Halogen Lamp Driver (Figure 8) The combi-
nation of an MIC5016/5017 and a power FET makes an
effective driver for a standard incandescent or halogen lamp
load. Such loads often have high inrush currents, as the
resistance of a cold filament is less than one-tenth as much as
when it is hot. Power MOSFETs are well suited to this
application as they have wider safe operating areas than do
power bipolar transistors. It is important to check the SOA
curve on the data sheet of the power FET to be used against
the estimated or measured inrush current of the lamp in
question prior to prototyping to prevent “explosive” results.
Motor Driver With Stall Shutdown (Figure 10) Tachometer
feedback can be used to shut down a motor driver circuit when
a stall condition occurs. The control switch is a 3-way type; the
“START” position is momentary and forces the driver ON.
When released, the switch returns to the “RUN” position, and
the tachometer’s output is used to hold the MIC5016 input ON.
If the motor slows down, the tach output is reduced, and the
MIC5016 switches OFF. Resistor “R” sets the shutdown
threshold.
If overcurrent sense is to be used, first measure the duration
of the inrush, then use the topology of Figure 5 with the RC of
the timer chosen to accomodate the duration with suitable
guardbanding.
12V
10µF
Control Input
ON
OFF
1/2 MIC5016
V+
Input
Source
Gnd Gate
IRF540
12V
330kΩ
R
330kΩ
10µF
1/2 MIC5016
V+
Input
Source
Gnd Gate
IRFZ44
1N4148
T
M
OSRAM
HLX64623
Figure 8: Halogen Lamp Driver
Figure 10. Motor Stall Shutdown
Relay Driver (Figure 9) Some power relay applications re-
quire the use of a separate switch or drive control, such as in
the case of microprocessor control of banks of relays where
a logic level control signal is used, or for drive of relays with
high power requirements. The combination of an MIC5016/
5017 and a power FET also provides an elegant solution to
power relay drive.
Simple DC-DC Converter (Figure 11) The simplest applica-
tion for the MIC5016 is as a basic one-chip DC-DC converter.
As the output (Gate) pin has a relatively high impedance, the
output voltage shown will vary significantly with applied load.
10µF
Control Input
ON
OFF
1/2 MIC5016
V+
Input
Source
Gnd Gate
12V
IRF540
Guardian Electric
1725-1C-12D
5V
10µF
1/2 MIC5016
V+
Input
Source
Gnd
Gate
V_OUT = 12V
Figure 9: Relay Driver
Figure 11. DC - DC Converter
MIC5016/5017
8
October 1998