Power Electronics
85-V Half Bridge MOSFET Driver Has Adaptive Dead Time, Shoot-Through Protection

85-V Half Bridge MOSFET Driver Has Adaptive Dead Time, Shoot-Through Protection

 

The MIC4605 from Micrel, Inc., is an 85V Half Bridge MOSFET driver ihat 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 5.5 V to 16 V operating supply range to maximize system efficiency. The low 5.5 V operating voltage allows longer run times in battery powered applications. These features make the MIC4605 an ideal solution for the industry's most demanding 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 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 85 V 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 an ideal solution for low voltage and high voltage applications.

The MIC4605 features fast 30 ns propagation delay times and 35 ns driver rise/fall times for a 1 nF 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  2.5 mm × 2.5 mm TDFN package. Both packages have an operating junction temperature range of -40 °C to +125 °C.

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