Microchip Technology

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  • 85V Half Bridge MOSFET Drivers

  • Created: Jul 19, 2016

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The reference design is a typical application of H-bridge configuration using a DC motor as a circuit load. In this reference design, MIC4604 is used which is an 85V half bridge MOSFET driver. These MOSFET drivers have a 5.5V-16V gate drive supply voltage range. The MIC4604 features a TTL input threshold, which includes a high-voltage internal diode that aid the high-gate drive bootstrap capacitor to charge. The MIC4604 has a fast 39ns propagation delay times and 20ns driver rise/fall times for a 1nF capacitive load.

The reference design utilized H-bridge configuration, which primarily function as a switch that enables the motor to rotate either clockwise or counterclockwise. Both U2 and U3 are MIC4604. The microcontroller can be programmed by the user to assign U2 for the clockwise rotation and U3 for the counterclockwise rotation. The MIC4609 is designed to independently drive high-side and low-side N-channel MOSFETs. This MOSFET driver contains an input buffer with hysteresis, Undervoltage-Lockout (UVLO) circuit and an output buffer. The high-side output of the buffer contains a high-speed level shifting circuit that gets its reference to the HS pin. The UVLO circuit forces the driver output low until the supply voltage exceeds the UVLO threshold. The low-side UVLO circuit monitors the voltage between VDD and VSS pins, while on the high-side UVLO circuit monitors the voltage between HB and HS pins.

The MIC4609 MOSFET drivers can be used in applications such as power inverters, high-voltage step-down regulators, computing peripherals and distributed power systems. The MIC4609 is available in both 8-pin SOIC package and a tiny 10-pin TFDN package with an operating junction temperature range of -40 to 125 degree Celsius.