• The EUU-7-101990000 circuit card is designed to drive semiconductor devices arranged in a bridge configuration.  The circuit provides four outputs, completely isolated from the input, and with three isolated output sections.

• The circuit also provides over-current protection with soft-shutoff.  The collector to emitter (drain to source) voltage is monitored on the two lower devices only.  Upon detection of a fault the two lower gate drive signals are removed, and the gate is pulled low through a resistor sized to turn the device off slowly.  The slow-shutoff is necessary to prevent an over-voltage condition at device turn-off, due to the large currents being commutated off in the device.  The fault is transmitted to the input side through an opto-coupler.  The fault signal is normally high (requires external pull-up) and goes low to indicate a fault.  The circuit automatically resets in approximately 50mSeconds.  The fault signal is externally latched, and the gate signals removed, until a user reset.

  Terminal Connections

• N/a

• This circuit requires no user adjustments.  The board has been configured at the component level for this application.