ATA6824 ATMEL Corporation, ATA6824 Datasheet - Page 12

• Manufacturer Part Number: ATA6824
• Description: High Temperature H-bridge Motor Driver
• Manufacturer: ATMEL Corporation

5.10
12
Short Circuit Detection
ATA6824 [Preliminary]
Figure 5-4.
The delays t
To detect a short in H-bridge circuitry, internal comparators detect the voltage difference
between source and drain of the external power NMOS. If the transistors are switched ON and
the source-drain voltage difference is higher than the value V
> t
immediately. The diagnostic pin DG1 will be set to “H”. With the next transition on pin PWM, the
bit will be cleared and the corresponding drivers, depending on the DIR pin, will be switched on
again.
There is a PBAT supervision block implemented to detect the possible voltage drop on PBAT
during a short circuit. If the voltage at PBAT falls under V
> t
above.
PWM or
DIR
Lx
Hx
SC
SC
(typically 10 µs) the signal SC (short circuit) will be set and the drivers will be switched off
the drivers will be switched off immediately and DG1 will be set to “H”. It will be cleared as
HxLH
Timing of the Drivers
and t
LxLH
t
LxHL
t
CC
include the cross conduction time t
t
HxLH
t
Lxf
50%
t
Hxr
80%
20%
80%
20%
t
t
HxHL
CC
t
SCPB
LxLH
t
Hxf
CC
SC
(5.6V with tolerances) for a time
.
(4V with tolerances) for a time
t
Lxr
4931C–AUTO–09/06
t
t
t