ata6838 ATMEL Corporation, ata6838 Datasheet - Page 7

• Manufacturer Part Number: ata6838
• Description: Ata6838 Hex Half-bridge Driver With Serial Input Control
• Manufacturer: ATMEL Corporation

3.2
3.3
3.4
3.5
3.6
4954C–AUTO–09/07
Power-supply Fail
Open-load Detection
Overtemperature Protection
Short-circuit Protection
Inhibit
In case of undervoltage at pin VS, an internal timer is started. When during a permanent under-
voltage the delay time (t
set and all outputs are disabled. When normal voltage is present again, the outputs are enabled
immediately. The PSF bit remains high until it is reset by the SRR bit in the input register.
If the open-load detection bit (OLD) is set to low, a pull-up current for each high-side switch and
a pull-down current for each low-side switch is turned on (open-load detection current I
I
tion), the corresponding bit of the output in the output register is set to high. Switching on an
output stage with OLD bit set to low disables the open load function for this output.
If the junction temperature exceeds the thermal prewarning threshold, T
prewarning bit (TP) in the output register is set. When the temperature falls below the thermal
prewarning threshold, T
a complete 16-bit data word: with CS = high to low, the state of TP appears at pin DO. After the
microcontroller has read this information, CS is set high and the data transfer is interrupted with-
out affecting the state of the input and output registers.
If the junction temperature exceeds the thermal shutdown threshold, T
disabled and all bits in the output register are set high. The outputs can be enabled again when
the temperature falls below the thermal shutdown threshold, T
been written to the SRR bit in the input register. Thermal prewarning and shutdown threshold
have hysteresis.
The output currents are limited by a current regulator. Current limitation takes place when the
overcurrent limitation and shutdown threshold (I
internal timer is started. The shorted output is disabled when during a permanent short the delay
time (t
cuit detection bit (SCD) is set. If the temperature prewarning bit TP in the output register is set
during a short, the shorted output is disabled immediately and SCD bit is set. By writing a high to
the SRR bit in the input register, the SCD bit is reset and the disabled outputs are enabled.
There are two ways to inhibit the ATA6838:
In both cases, all output stages are turned off but the serial interface stays active. The output
stages can be activated again by bit SI = 1 (when INH = VCC) or by pin INH switched back to
VCC (when SI = 1).
LS1-6
• Set bit SI in the input register to 0
• Switch pin INH to 0V
). If V
dSd
) programmed by the short-circuit timer bit (SCT) is reached. Additionally, the short-cir-
VS
– V
HS1-6
or V
jPW
dUV
LS1-6
reset, the bit TP is reset. The TP bit can be read without transferring
) is reached, the power supply fail bit (PSF) in the output register is
is lower than the open-load detection threshold (open-load condi-
HS1-6
ATA6838 [Preliminary]
, I
LS1-6
) are reached. Simultaneously, an
j switch on
j switch off
jPW
, and when a high has
set, the temperature
, the outputs are
HS1-6
7
,