5.15.6 OUTPUT CURRENT LIMITATION

The ATA6847 provides an output current limitation feature for monitoring the external power MOSFETs sum current. The output of OpAmp3 is internally connected to a comparator. The limitation voltage is set in the ILIMTH Register. The limitation feature is active in Device Normal mode as soon as it is activated via the ILIMEN bit, see the ILIMCR Register below.

On a current limitation event, different reactions can be configured, as follows:
  • If the ILIMSDEN bit is set to ’1’ (latched behavior), the interrupt event is latched and the GDU will switch into GDU Standby mode.
  • If the ILIMSDEN bit is set to ’0’ (unlatched behavior), GDU Normal mode is maintained, but the six GHx and GLx gate driver outputs are deactivated until ILIM condition is resolved.

The interrupt register bit “ILIM” (see SIR1 Register) will be set, and an interrupt will be generated under the following conditions:

  • Unlatched fault handling (ILIMEN = ’1’ AND ILIMSDEN = ’0’) and ILIMECE bit is set to ‘1’; or
  • Latched fault handling (ILIMEN = ’1’ AND ILIMSDEN = ’1’)

The interrupt register bit “ILIM” will be cleared under the following conditions:

  • When any of the six gate driver outputs become active while the unlatched fault handling is enabled; or
  • When the ILIM bit is set to ‘1’ via SPI.

The ATA6847 will ignore any current limitation event if the ILIMEN bit is set to ‘0’.

The current limitation detection delay filter can be configured using ILIMFLT in the ILIMCR Register. The following table explains the ILIM control bits in more detail:

ILIMEN

ILIMECE

ILIMSDEN

Device Behavior

0

0/1

0

No action on current limitation events

0

0/1

1

No action on current limitation events

1

1

0

Interrupt generation, unlatched automatic fault handling, interrupt event delay is inactive as soon as the interrupt bit is reset by the gate control.

1

0

0

No interrupt, unlatched automatic fault handling

1

0/1

1

Interrupt generation and latched fault handling