85V Half-Bridge MOSFET Driver
Created: Jun 16, 2016
No description available.
This reference design features MIC4605 85V half-bridge MOSFET driver. This device has an adaptive-dead-time and shoot-through protection. The adaptive-dead-time circuitry monitors the half-bridge outputs to minimize the time between high-side and low-side MOSFET transitions, thus maximizing efficiency. The anti-shoot-through circuitry prevents erroneous inputs and noise from turning both MOSFETs ON at the same time. Furthermore, the MIC4605’s adjustable gate drive sets the gate drive voltage to VDD for optimal MOSFET Rds (on), which minimizes power loss due to the MOSFET’s Rds (on).
This design requires a 5.5V-16V-power supply to power the VDD terminal (J1) of the MIC4605. This also accepts a voltage up to 85V at the VIN terminal. This 85V may be used to power the MOSFETs. Both the HI/LI pins are TTL-compatible and can be used with input signals with amplitude less than the supply voltage. The threshold level is independent of the VDD supply voltage and there is no dependence between IVDD and the input signal amplitude with the MIC4605. This feature makes the MIC4605 a good level translator that will drive high-threshold MOSFETs. A low-power, high-speed, level-shifting circuit isolates the low side (VSS pin) from the high side (HS pin). Power to the high-side driver and UVLO circuit is supplied by the bootstrap circuit, which consists of an internal diode and an external capacitor C2.
The MIC4605 MOSFET drivers are widely used in DC motor applications. In the particular design, it is used as half-bridge driver in which the turn in one direction only. The target applications of this device include fans, power inverters, high-voltage step down regulators, motor control, appliances, and e-bikes.