IX6611

R00A

PRELIMINARY

13

over current occurs the Output Faults Pulse Generator

creates a narrow 200ns pulse that will be used by the

Fault Control Logic to communicate the fault condition

to the primary side across the barrier.

3.1.10

5V Regulator

The 5V regulator provides power to the internal low

voltage circuits that are referenced to VEE. Regulator

required to provide the transient currents.

3.1.11

Under Voltage and Over Voltage Lockout

IX6611 contains an Under Voltage Lockout

Comparator (UVLO COMP) and an Over Voltage

Lockout Comparator (OVLO COMP). These

comparators monitor the positive power supply

beginning of each PWM cycle, if the difference in

threshold or above the OVLO threshold the gate driver

output is disabled (driven low) for that PWM cycle.

Once the PWM cycle starts with no power supply

faults then the gate driver is enabled and the UVLO

and OVLO faults are ignored for the reminder of the

cycle. Power supply fault are not latched. Normal

operation resumes automatically on the next PWM

input cycle after the power supply recovers from the

fault condition.

raises above the UVLO threshold.

3.1.12

Fault Control Logic

Fault information is communicated to the primary side

through the pulse transformer interface. Fault Control

Logic provides the gate drive to the high current

switches connected to the primary terminals of the

pulse transformer. Narrow pulses are used to drive the

high current switches. Based on the fault type, the fault

control logic selects the narrow pulses either from the

input interface or from the output fault pulse generator

and drives the appropriate high current switch.

UVLO fault condition is communicated to the primary

side by driving the FLT1 high current switch on the

leading edge of the PWM gate drive ON cycle.

OVLO fault condition is communicated to the primary

side by driving the FLT1 high current switch on the

leading edge and the FLT2 high current switch on the

trailing edge of the PWM gate drive ON cycle. The

primary side recognizes the OVLO fault condition if

and only if both FLT1 and FLT2 flags are set.

IGBT Over Current condition is communicated to the

primary side by driving the FLT2 high current switch

with a pulse from the output fault pulse generator.