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need a little help with a motor control circuit

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  • need a little help with a motor control circuit

    I am currently building a motorized vehicle as a student at Clarkson University. It has two motors each driven by an HIP4081A IC. The two general schematics are here and here

    My problem is on the DISable input. When the motor is enabled, the input on this pin should be 0, however it is around 2.5 volts so it never leaves disable mode. When I remove the IC, all of the input voltages test fine and even when the IC is in the 4 bridge inputs are ok just the DIS is not. I have the pin tied to ground with a 100k resistor and the three inputs coming into this pin (from the joystick logic circuit not shown) isolated with small signal diodes. When it is supposed to be enabled, the 3 inputs on are 0 but on the other side of the diodes where they meet it and go to the DIS pin its about 2.5 volts and 5 volts when disabled.

    I have already fried one of these chips by grounding out the DIS pin directly. Can anyone offer any advice?

    Thanks a million