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Pete,
please could you please send a schematic of all
this I know I will need it.
Hank
----- Original Message -----
Sent: Saturday, November 28, 2009 1:37
PM
Subject: Re: [WheelCommander]
WC-132
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:
Hi Pete,
I have two high powered H-Brides there
driver consist of the HIP-4081A and I am working on interfacing the
HIP-4081A H-Bridge driver to your WC-132.
I want to use the dual-dir-h-bridge capability
on the WC-132 but the schematic dated
2/172008 is not quit clear to me on how the reverse would have to
work.
This is a schematic of the H-Bridge I intent to
use Page 108, stamp BS2 is excluded, see
attachment
I hope you can help me. Regards, Hank van
Buuren.
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