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MIC4605 Evaluation Board
85V Half-Bridge MOSFET Drivers
with Adaptive Dead Time and
Shoot-Through Protection
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
November 18, 2013
Revision 1.0
General Description
The MIC4605 is an 85V half-bridge MOSFET driver that
features adaptive-dead-time and shoot-through protection.
The adaptive-dead-time circuitry actively monitors the half-
bridge outputs to minimize the time between high-side and
low-side MOSFET transitions, thus maximizing power
efficiency. Anti-shoot-through circuitry prevents erroneous
inputs and noise from turning both MOSFETs on at the
same time. Additionally, the MIC4605’s adjustable gate
drive sets the gate drive voltage to VDD for optimal
MOSFET R
DS(ON)
, which minimizes power loss due to the
MOSFET’s R
DS(ON)
.
Requirements
At a minimum, the evaluation board requires a 5.5V to 16V
power supply to power the VDD terminal (J1) of the
MIC4605 and another supply (up to 85V) may be used to
power the MOSFETs connected to the VIN terminal (J2). A
pulse generator or the output of a PWM control IC may be
connected to the HI and LI terminals (−1), or PWM single
input (−2).
Precautions
There is no reverse input protection on this board. When
connecting the input sources, make sure that the correct
polarity is observed.
Under extreme load conditions and with a high supply
voltage (>48V) connected to the VIN terminal (J2), input
transients can be quite large if long test leads are used. In
such cases a 100µF, 100V electrolytic capacitor is needed
across the VIN terminals to prevent overvoltage damage to
the IC. This can be removed if a clean supply voltage on
VIN is always guaranteed.
Datasheets and support documentation are available on
Micrel’s web site at: www.micrel.com
.
Getting Started
1. Connect VIN supply between the VIN and GND
terminals and VDD supply between the VDD and
GND terminals.
Connect a supply between the VIN terminal (J2) and
the GND terminal (J3), paying careful attention to
polarity and supply range (VIN ≤ 85V). Do not apply
power until Step 5.
Connect a supply between the VDD terminal (J1) and
the GND terminal (J3), paying careful attention to
polarity and supply range (5.5V ≤ VDD < 16V). Do not
apply power until Step 5.
2. Connect the TTL-compatible HI and LI inputs (
−
1),
or the PWM single input (
−
2).
Connect the HI input (JP2) and LI input (JP3) to a
pulse generator or the output of a PWM control IC.
Ensure that they are non-overlapping signals and are
TTL compatible logic-levels. The PWM single input
replaces the HI input (JP2) for the −2 option.
3. Monitor inputs and outputs.
Monitor the inputs HI (JP2) and LI (JP3) or PWM (JP2)
and outputs HO (JP1) and LO (JP4) with an
oscilloscope.
4. Connect motor across HS and GND or connect HS
to GND.
The simplest way to observe the MIC4605 operation is
to connect a motor across the HS terminal (J8) and
GND (J9). Alternatively the HS terminal (J8) can be
shorted to GND (J9) with the VIN supply turned OFF.
DC and AC parameters can be easily measured in this
configuration.
5. Turn-on supplies and HI/LI inputs.
Turn-on the VDD power supply, followed by the VIN
power supply. Turn on the HI and LI inputs (−1) or
PWM single input (−2).
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