Demand Peripherals             Robotics and Automation Made Easy


D7HB: Dual 7 Amp H-Bridge Card

The electronics in the dual 7 amp H-Bridge card work with the logic in a Baseboard FPGA card to form either a dual DC motor controller or a bipolar stepper motor controller.


- 7 Amp continuous current
- 12 Amp peak current
- Up to 18 volt input
- High current FET drivers for high frequency PWM
- Modes include Forward, Reverse, Brake, and Coast


The schematic and layout of the D7HB are shown below. The Eagle schematic and board files are available here: d7hb.sch and d7hb.brd. The bill-of-materials is available here: d7hb.txt.



When used with the "dc2" peripheral this interface card can provide direction, PWM speed control, and both brake and coast for two motors. The card uses four pins from the FPGA, two pins for each motor. The outputs are labeled 1 and 2 on the card. The table below shows the translation of the inputs input pin values to modes.

INPUT    MODE         OUT1       OUT2
 00      Coast        low        low
 01      Forward      low        (PWM)
 10      Reverse      (PWM)      low
 11      Brake        high       high     The power-on default

When used with the polar stepper controller peripheral ("bstep") this interface card can provide direction, step rate, step count, and holding current for a bipolar stepper motor with a current rating of up to 7 amps and a voltage rating of up to 18 volts.