ATA6834-DK Atmel, ATA6834-DK Datasheet - Page 11

• Manufacturer Part Number: ATA6834-DK
• Description: BOARD BLDC MOTOR CTRL ATA6833/34
• Manufacturer: Atmel
• Type: MOSFET & Power Driverr

Specifications of ATA6834-DK

• Main Purpose: Power Management, Motor Control
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: ATA6833 / ATA6834, ATmega32M1
• Primary Attributes: 3-Ph BLDC, IC with FET Driver, LIN Transceiver, Volt Regulator, Watchdog
• Secondary Attributes: LCD with Touch Screen on MCU Controller Board
• Product: Power Management Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3.8
3.9
9122G–AUTO–10/10
Short Circuit Detection
Cross Conduction Timer
Short circuits in the motor bridge circuitry are sensed by S1 to S3 inputs. Internal comparators
monitor the voltage differences between the drain and the source terminals of the external
power-NMOS transistors. If one transistor switches on and its drain-source voltage exceeds
V
cuit in this branch will be detected. In this case, all output drivers will be switched off
immediately and pin DG1 will be set to HIGH. With a rising edge at any of the pins IL1 to IL3 or
IH1 to IH3, the diagnostic output DG1will be reset and the drivers can be switched on again.
In order to prevent damage of the motor bridge due to peak currents a non-overlapping phase
for switching the power-NMOS transistors is mandatory. Therefore, a cross conduction timer
has been implemented to prevent switching on any output driver for a time t
driver has been switched off. This also accounts for toggling any other driver after a short cir-
cuit was detected. An external RC parallel combination defines the value for t
estimated as follows:
page
The RC combination is connected between CC and GND pins. When one of the drivers has
been switched off the RC combination is charged to 5V (VINT) and discharged with its time
constant. Any low to high transition at the control inputs will be masked out at the driver out-
puts until the voltage at CC pin drops below 67% of its initial value (VINT). The timer will be
re-triggered at any time by any falling edge at the control inputs. This is shown in the following
figure.
Figure 3-6.
t
CC
SC
= K
threshold (typically 4V) after a blanking time t
16.
CC
IH1
CC
IL1
IL3
H1
L1
L3
R
CC
Interaction of Short Circuit Detection and Cross Conduction Timer
V
V
(k )
CC
CC
if V
Atmel ATA6833/ATA6834 [Preliminary]
= V
= 67% V
PBAT
Shut off
VINT
- V
C
S1
CC
VINT
> 4V
(nF), K
t
cc
CC
for t
for t
is specified in
Ignore V
Ignore V
SC
SC
= 6µs
= 6µs
S1
S3
SC
if V
if V
Shut off
Shut off
S1
S3
(typically 6µs, see
Section 8. “Electrical Characteristics” on
> 4V
> 4V
t
cc
t
cc
Ignore V
Figure
for t
SC
PBAT
CC
= 6µs
3-6), a short cir-
after any other
- V
CC
S1
and can be
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