TLE 6711G Infineon Technologies, TLE 6711G Datasheet - Page 11

• Manufacturer Part Number: TLE 6711G
• Manufacturer: Infineon Technologies

Specifications of TLE 6711G

• Packages: PG-DSO-14
• Comment: -
• Vq (max): 5.0V
• Iq (max): 250.0 mA
• Iq (typ): 1,500.0 µA
• Output: Boost/Buck Conv.

4.3
The TLE 6711 G/GL contains a fully integrated boost converter (except the boost-diode), which provides a supply
voltage for an energy reserve e.g. an airbag firing system. The regulated boost output voltage
programmable by a divider network (external resistors) providing the feedback voltage for the boost feedback pin
BOFB. The energy which is stored in the external electrolytic capacitor at
even if the battery is disconnected by a car crash.
The boost inductance
with a programmable (external resistor
An internal bandgap reference provides a temperature independent, on chip trimmed reference voltage for the
regulation loop. An error amplifier compares the reference voltage with the boost feedback signal
external divider network (determination of the output boost voltage
Application note for programming the output voltage at pin
V
With a PWM (Pulse Width Modulation) comparator the output of the error amplifier is compared to a periodic linear
ramp, provided by a sawtooth signal of the oscillator connected to pin R. A logic signal with variable pulse width
is generated. It passes through the logic circuits (sets the output latch PWM-FF) and driver circuits to the power
switching DMOS. The Schmitt-trigger output resets the output flip-flop PWM-FF by NOR 2. The PWM signal is
gated by the NAND 2 to guarantee a dominant reset.
Figure 8
Figure 8
condition. The output transistor is switched off immediately if the overcurrent comparator detects an overcurrent
level at the power DMOS or if the sense output switches to low induced by a
Data Sheet
BOOST
V
Boost
BOFB
Pin 12
R
Pin 1
10
V
2.8 V
=
V
thUV
4 V
shows the most important waveforms during operation; for low, medium and high loads up to overload
REF
A
V
GND
GND
I
GND
Pullup
=
=
Boost Converter
BOFBTH
=
Boost Converter Block Diagram
V
38 V
thOV
OV
COMP
UV
COMP
Error
AMP
-
+
+
-
+
-
L when
OV at
L when
T
L
j
H when
V
H when
Overcurrent
-------------------------------------
> 175 ˚C
Boost
R
BO
Oscillator
V
V
V
BO1
max
Boost
min
< 4 V
(typ. 100 H) is PWM-switched by an integrated current limited power DMOS transistor
R
NAND 3
BO2
+
t
r
&
t
R
f
t
BO2
r
H when
T
or OV at
t
j
> 175 ˚C
NOR 1
1
R
Ramp
V
R
Boost
) frequency.
L when
Error
NAND1
Schmitt-trigger 1
&
V
V
high
low
R
S
t
Error-FF
r
t
&
&
f
Error-Signal
Error-Ramp
t
r
Q
Q
11
t
H when
Error
Clock
V
BOOST
H when Outputcurrent > 1.2 A
PWM
COMP
Error
Gate
NOR 2
-
+
1
:
V
NAND 2
H when
Error-Signal
<
Error-Ramp
BOOST
Detector
&
Unlock
V
R
S
BOOST
).
PWM-FF
&
&
V
BOOST
Q
Q
guarantees accurate airbag firing,
H =
OFF
OC
COMP
INV
undervoltage command.
1
-
+
H =
ON
Rev. 3.4, 2007-08-16
Gate
Driver
Circuit Description
V
18 mV
Boost Status
Low if Battery
Disconnected
thOC
V
BOI
Pin 14
BOFB
Power
D-MOS
TLE 6711
14.5 m
R
BOGND
Pin 13
AEB02946
Sense
OVL
Pin 11
V
GND
from the
BOOST
(1)
is