MIC5020 Micrel, Inc. MIC5020
Current-Sensing Low-Side MOSFET Driver General Description Features The MIC5020 low-side MOSFET driver is designed to operate
at frequencies greater than 100kHz (5kHz PWM for 2% to
100% duty cycle) and is an ideal choice for high-speed applications such as motor control, SMPS (switch mode power
supplies), and applications using IGBTs. The MIC5020 can
also operate as a circuit breaker with or without automatic
retry. The MIC5020’s maximum supply voltage lends itself
to control applications using up to 50V. The MIC5020 can
control MOSFETs that switch voltages greater than 50V.
A rising or falling edge on the input results in a current source
or sink pulse on the gate output. This output current pulse
can turn on or off a 2000pF MOSFET in approximately 175ns.
The MIC5020 then supplies a limited current (< 2mA), if
necessary, to maintain the output state.
An overcurrent comparator with a trip voltage of 50mV makes
the MIC5020 ideal for use with a current sensing MOSFET.
An external low value resistor may be used instead of a
sensing MOSFET for more precise overcurrent control. An
optional external capacitor connected to the CT pin may be
used to control the current shutdown duty cycle from 20%
to < 1%. A duty cycle from 20% to about 75% is possible
with an optional pull-up resistor from CT to VDD. An open
collector output provides a fault indication when the sense …
