Datasheet

Data Sheet 4 Rev. 2.8, 2007-03-20
TLE 4263
Circuit Description
The control amplifier compares a reference voltage, which is kept highly accurate by
resistance adjustment, to a voltage that is proportional to the output voltage and drives
the base of the series transistor via a buffer. Saturation control as a function of the load
current prevents any over-saturation of the power element. If the externally scaled down
output voltage at the reset threshold input drops below 1.35 V, the external reset delay
capacitor is discharged by the reset generator. When the voltage of the capacitor
reaches the lower threshold
V
DRL
, a reset signal occurs at the reset output and is held
until the upper threshold
V
DU
is exceeded. If the reset threshold input is connected to
GND, reset is triggered at an output voltage of typ. 4.65 V. A connected microcontroller
will be monitored through the watchdog logic. In case of missing pulses at pin W, the
reset output is set to low. The pulse sequence time can be set in a wide range with the
reset delay capacitor. The IC can be switched at the TTL-compatible, low-active inhibit
input. The IC also incorporates a number of internal circuits for protection against:
• Overload
• Overtemperature
• Reverse polarity
Figure 2 Block Diagram
Input
AEB03068
INH
GND
Output
D
RO
RADJ
Reset
Delay
Reset
Output
Reset
Threshold
Watchdog
W
Temperature
Sensor
Generator
Reset
Reference
Bandgap
Adjustment
Buffer
Control
Amplifier
Saturation
Control and
Protection
Circuit
Inhibit
Ι Q
GND