TLE7368G Infineon Technologies, TLE7368G Datasheet - Page 24

• Manufacturer Part Number: TLE7368G
• Description: IC REGULATOR LDO DSO-36
• Manufacturer: Infineon Technologies

Specifications of TLE7368G

• Applications: Automotive
• Voltage - Supply: 4.5 V ~ 45 V
• Operating Temperature: -40°C ~ 150°C
• Mounting Type: Surface Mount
• Package / Case: DSO-36
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Supply: -
• Other names: SP000104573; TLE7368G; TLE7368GNT; TLE7368GT; TLE7368GTR

5
In the following the main circuit blocks of the TLE7368, namely the Buck converter, the linear regulators, the
trackers, the charge pump, the enable and reset circuits and the watchdog are described in more detail.
5.1
The TLE7368’s DC to DC converter features all the functions necessary to implement a high efficient, low emission
Buck regulator with minimum external components. The step down regulator in the TLE7368 follows a concept
similar to the one of its predecessor, TLE6368, which allows operation over a battery voltage range from as low
as 4.5 V up to a maximum of 45 V at peak currents of 2.5 A at minimum.
converter with its major components, i.e. the internal DMOS power stages, the high side driver including its supply
scheme, the power stage slope control circuit for reduced EME, the current mode control scheme and various
protection circuits for safe converter operation.
5.1.1
The step down converter’s control method is based upon the current mode control scheme. Current mode control
provides an inherent line feed forward, cycle by cycle current limiting and ease of loop compensation. No external
compensation components are needed to stabilize the loop, i.e. the operation of the Buck converter. The slope
compensation circuit in addition to the current sense amplifier and the error amplifier prevents instabilities/sub
harmonic oscillations at duty cycles higher than 0.5. The cycle by cycle current limiting feature supports also a soft
start feature during power up. Additional implemented current blanking prevents faulty DMOS turn off signals
during switching operation.
5.1.2
The supply concept of the Buck converter’s power stage driver follows the Bootstrapping principle. A small external
capacitor, placed between pins SW and BST, is used to provide the necessary charge at the gate of the power
stage. The capacitor is refreshed at each switching cycle while the power stage is turned off resulting in the ability
to power the gate at the next turn on of the power stage.
In cases where the input/battery voltage approaches the nominal Buck converter output voltage, the duty cycle of
the converter increases. At the point where the power stage is statically turned on (100% duty cycle) a refresh of
the Bootstrap capacitor as described above is not possible. In this case the charge pump helps to accomplish the
gate over drive in order to keep the power stage turned on with low
before switching to 100% duty cycle, the device operates in pulse skipping mode. In this mode the device appears
to be operating at much lower frequencies with very small duty cycles. In real, the device is doing a few 100% duty
cycle periods followed by a period with a duty cycle smaller than 1.
Data Sheet
Detailed Internal Circuits Description
Buck Regulator
Buck Regulator Control Scheme
High Side Driver Supply and 100% Duty Cycle Operation
24
R
dson
Figure 3
Detailed Internal Circuits Description
. With decreasing input voltage, shortly
shows the block diagram of the
Rev. 2.1, 2010-11-22
TLE7368