EVAL6229QR STMicroelectronics, EVAL6229QR Datasheet - Page 20

• Manufacturer Part Number: EVAL6229QR
• Description: BOARD DEMO L6229Q BLDC MOT CTRL
• Manufacturer: STMicroelectronics
• Type: Motor / Motion Controllers & Driversr

Specifications of EVAL6229QR

• Main Purpose: Power Management, Motor Control
• Embedded: No
• Utilized Ic / Part: L6229Q
• Primary Attributes: 3-Ph BLDC, 8 ~ 52V Output, PWM Current Control, Brake Function
• Secondary Attributes: Over Current, Cross Conduction & Temperature Protection
• Maximum Operating Temperature: + 125 C
• Operating Supply Voltage: 8 V to 52 V
• Product: Power Management Development Tools
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: L6229Q
• Other names: 497-10748

Circuit description
5.7
20/28
Non-dissipative overcurrent detection and protection
The L6229Q integrates an overcurrent detection circuit (OCD) for full protection. This circuit
provides output-to-output and output-to-ground short circuit protection as well. With this
internal over current detection, the external current sense resistor normally used and its
associated power dissipation are eliminated.
overcurrent detection circuit.
To implement the over current detection, a sensing element that delivers a small but precise
fraction of the output current is implemented with each high side power MOS. Since this
current is a small fraction of the output current there is very little additional power
dissipation. This current is compared with an internal reference current I
output current reaches the detection threshold (typically I
comparator signals a fault condition. When a fault condition is detected, an internal open
drain MOS with a pull down capability of 4 mA connected to pin DIAG is turned on.
The pin DIAG can be used to signal the fault condition to a μC or to shut down the three-
phase bridge simply by connecting it to pin EN and adding an external R-C (see R
Figure 19. Overcurrent protection simplified schematic
Figure 20
recovering normal operation can be easily programmed by means of the accurate
thresholds of the logic inputs. It is affected whether by C
magnitude is reported in
an overcurrent has been detected depends only by C
Figure 22
C
the value of C
delay time and the R
The resistor R
values for R
disable time.
EN
μC or LOGIC
V
DD
is also used for providing immunity to pin EN against fast transient noises. Therefore
R
C
EN
EN
shows the overcurrent detection operation. The disable time t
EN
EN
DIAG
EN
and C
EN
should be chosen as big as possible according to the maximum tolerable
should be chosen in the range from 2.2 kΩ to 180 kΩ. Recommended
TO GATE
40Ω TYP.
R
LOGIC
DS(ON)
EN
EN
POWER SENSE
value should be chosen according to the desired disable time.
are respectively 100 kΩ and 5.6 nF that allow obtaining 200 μs
Figure
OPEN-DRAIN
INTERNAL
1 cell
COMPARATOR
Doc ID 15209 Rev 3
OCD
21. The delay time t
HIGH SIDE DMOS
POWER DMOS
OVER TEMPERATURE
n cells
I
1
OUT
I
1
/ n
1
I
I
I
REF
REF
1
+I
Figure 19
VS
2
+
/ n
A
OUT
I
2
DELAY
/ n
2
POWER DMOS
HIGH SIDE DMOS
I
2
EN
n cells
shows a simplified schematic for the
EN
value. Its magnitude is reported in
SOVER
before turning off the bridge when
and R
D02IN1381
POWER SENSE
I
= 2.8 A) the OCD
3
1 cell
/ n
EN
values and its
OUT
DISABLE
3
POWER DMOS
REF
I
3
VS
n cells
. When the
B
HIGH SIDE DMOS
before
POWER SENSE
EN
L6229Q
, C
1 cell
EN
).