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Hank, None of our example H-bridge configurations will work as-is with the HIP-4081A, though the dual-dir version is the place to start: http://nubotics.com/products/wc132/dual-dir-h-bridge.pdf The direction line control can be wired according to that diagram to the high side control pins, BHI and AHI. The low side, however, cannot be wired directly to the PWM output. Instead, you will need to add some logic between the WC-132 and the HIP-4081A to control which pin, BLI or ALI, receives the PWM signal based on the logic levels of the direction lines (L_DIR or R_DIR). You can implement this many different ways. One way is to get one quad 2 input AND gate package, such as the 74HC08. You will need to use two gates for each H-bridge. (Another way is to use two quad 2 input NAND gate packages to build AND gates out of NAND gates). Take the left wheel's H-bridge as an example, and assume the four gates in the AND package are designated A, B, C, D. Say you use AND gates A and B for the left wheel, and C and D for the right. The outputs of gates A and B would connect to the left wheel's HIP-4081A ALI and BLI pins respectively; we will selectively control these gates to only send the PWM signal to the side of the H-bridge we want to drive with the PWM signal; the other side will see a logic low on the lower FET input of the H-bridge but a logic high on the upper FET input. Now for the inputs to the gates. Connect L_PWM to one input of each gate A and B. Connect the L_DIR to the unused input on gate A, and /L_DIR (WC-132 DIO3, pin J4.4) to the unused input on gate B. For this to work, you need to have /L_DIR connected to AHI and L_DIR connected to BHI, with gate A's output is connected to ALI and gate B's output is connected to BLI. This way, when L_DIR is high, BHI's FET and ALI's FET will turn on when L_PWM is high, spinning the motor one way. When /L_DIR is high, AHI's FET and BLI's FET will turn on when L_PWM is high, spinning the motor the other way. When L_PWM is low, neither low-side FET will be on, allowing the motor to coast. You would do the same thing for the right H-bridge, only using gates C and D and the corresponding R_PWM, R_DIR, and /R_DIR signals. Hope this helps. I can do a diagram if you need it. -Pete Hank van Buuren wrote:
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