Batteries and Portable Power

85V Half-Bridge MOSFET Driver with Adaptive Dead Time and Shoot-Through Protection

Micrel, Inc. today introduced the MIC4605, a 85V Half Bridge MOSFET driver that features Adaptive-Dead-Time and Shoot-Through Protection. The Adaptive-Dead-Time circuitry actively monitors the Half Bridge to minimize the time between high and low side MOSFET transitions, which maximizes power efficiency. Anti-Shoot-Through circuitry prevents erroneous inputs and noise from turning both MOSFETs on at the same time. The MIC4605 also offers a wide 5.5V to 16V operating supply range to maximize system efficiency. The low 5.5V operating voltage allows longer run times in battery powered applications. The MIC4605 is suited for battery operated motor applications including power tools and power dc-ac inverters. The MIC4605 is currently available in volume with pricing starting at $0.55 for 1K quantities in a SOIC package option.

“The demand for higher efficiency is increasing via new government regulations. Since electrical motors are one of the largest consumers of electrical power, motor driver designers are in need of a more efficient and reliable solution,” noted Brian Hedayati, vice president of marketing, high-performance Linear and Power Solutions, Micrel. “The MIC4605 is one of the industry’s most robust and power efficient Half Bridge MOSFET drivers designed to address a wide variety of applications including motor drives, UPS and dc-ac inverters.”

The Adaptive-Dead-Time (ADT) circuitry actively monitors the MOSFETs in the Half Bridge switch circuit allowing only one MOSFET to be active at a time, thus assuring no cross conduction condition that can permanently destroy the Half Bride circuit. The ADT circuitry also keeps the transitions between High side and Low Side MOSFET as short possible to minimize power losses due to long dead-time the degrade the power efficiency. The ADT circuitry eliminates the need to design in dead-time margin and time delay between HI and LI inputs to protect against cross conduction reducing the headroom requirements of the microcontroller. In addition, the 85V operating voltage offers plenty of margin as protection against voltage spikes which are present in motor drive and power supply applications. This makes the MIC4605 suited for low-voltage and high-voltage applications.

The MIC4605 features fast 30ns propagation delay times and 35ns driver rise/fall times for a 1nF capacitive load. For MIC4605 -1, TTL inputs provide independent control of the low-side and high-side gate drivers. The MIC4605 -2 has a single PWM input for both low-side and high-side gate drivers. The outputs do not overlap in either mode. An internal, high-voltage Schottky diode charges the high-side, gate-drive bootstrap (external) capacitor. The MIC4605 is available in an 8-pin SOIC package and a tiny 10-pin 2.5mm - 2.5mm TDFN package. Both packages have an operating junction temperature range of 40 to +125 degrees C.

Micrel, Inc.
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