MIC5060_10 Datasheet, PDF (11/12 Pages) Micrel Semiconductor – Ultra Small High-Side MOSFET Driver

Micrel, Inc.
Relay Driver
Some power relay applications require 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
MIC5060 and a power FET also provides an elegant
solution to power relay drive.
MIC5060
Simple DC-DC Converter
The simplest application for the MIC5060 is as a basic
one-chip DC-DC converter.
As the output (Gate) pin has relatively high impedance,
the output voltage shown will vary significantly with
applied load.
Figure 8. Relay Driver
Motor Driver with Stall Shutdown
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 MIC5060 input
ON. If the motor slows down, the tach output is reduced,
and the MIC5060 switches OFF. Resistor “R” sets the
shutdown threshold.
Figure 10. DC-DC Converter
High Side Driver with Load Protection
Although the MIC5060 is reverse battery protected, 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.
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)
Figure 9. Motor Stall Shutdown
February 2010
Figure 11. High-Side Driver with Load Protection
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M9999-021610-C