Datasheet

6Atmel ATA6826C [DATASHEET]
9213D–AUTO–09/12
3.2 Power-supply Fail
In case of undervoltage at pin VS, the Power-Supply Fail bit (PSF) in the output register is set and all outputs are disabled. To
detect an undervoltage, its duration has to be longer than the undervoltage detection delay time t
dUV
. The outputs are enabled
immediately when supply voltage recovers to a normal operating value. The PSF bit stays high until it is reset by the SRR
(Status Register Reset) bit in the input register.
3.3 Open-load Detection
If the current through a high-side or low-side switch in the ON-state stays below the open-load detection threshold, the open-
load detection bit (OPL) in the output register is set.
The OPL bit stays high until it is reset by the SRR bit in the input register. To detect an open load, its duration has to be longer
than the open-load detection delay time t
dSd
.
3.4 Overtemperature Protection
If the junction temperature of one or more output stages exceeds the thermal prewarning threshold, T
jPW set
, the temperature
prewarning bit (TP) in the output register is set. When the temperature falls below the thermal prewarning threshold, T
jPW reset
,
the bit TP is reset. The TP bit can be read without transferring a complete 16-bit data word. The status of TP is available at pin
DO with the falling edge of CS. After the microcontroller has read this information, CS is set high and the data transfer is
interrupted without affecting the status of input and output registers.
If the junction temperature of one or more output stages exceeds the thermal shutdown threshold, T
j switch off
, all outputs are
disabled and the corresponding bits in the output register are set to low. The outputs can be enabled again when the
temperature falls below the thermal shutdown threshold, T
jswitch on
and the SRR bit in the input register is set to high. Hysteresis
of thermal pre-warning and shutdown threshold avoids oscillations.
3.5 Short-circuit Protection
The output currents are limited by a current regulator. Overcurrent detection is activated by writing a high to the OCS
(Overcurrent Shutdown) bit in the input register. When the current in an output stage exceeds the overcurrent limitation and
shutdown threshold, it is switched off after a delay time (t
dSd
). The short-circuit detection bit (SCD) is set and the corresponding
status bit in the output register is set to low. For OCS = low the overcurrent shutdown is inactive. The SCD bit is also set if the
current exceeds the overcurrent limitation and shutdown threshold, but the outputs are not affected. By writing a high to the
SRR bit in the input register the SCD bit is reset and the disabled outputs are enabled.
3.6 Inhibit
Applying 0V to pin 10 (INH) inhibits the Atmel
®
ATA6826C.
All output switches are then turned off and switched to tri-state. The data in the output register is deleted. The current
consumption is reduced to less than 2µA at pin VS and less than 25µA at pin VCC. The output switches can be activated again
by switching pin 10 (INH) to 5V which initiates an internal power-on reset.