tle4226 Infineon Technologies Corporation, tle4226 Datasheet - Page 5

• Manufacturer Part Number: tle4226
• Description: Intelligent Sixfold Low-side Switch
• Manufacturer: Infineon Technologies Corporation

TLE 4226 G
Circuit Description
Input Circuits
The control inputs and the preferred-state input consist of TTL-compatible Schmitt triggers with
hysteresis. Driven by these stages the buffer amplifiers convert the logic signal necessary for
driving the NPN power transistors.
Switching Stages
The output stages consist of NPN power transistors with open collectors. Each stage has its own
protective circuit for limiting power dissipation and shorted load current, which makes the outputs
shorted load protected to the supply voltage throughout the operating range. Integrated clamp-
diodes limit positive voltage spikes that occur when inductive loads are discharged. Output currents,
caused through negative voltages at the outputs, are compensated up to 50 mA for all outputs in
total.
Monitoring and Protective Functions
Each output is monitored (for overload) in its activated status. For the switches 1 to 4 overload is
detected, if the switches are activated and the output voltage at the transistor is higher than 4.1 V
for more than 10 µ s. The concerned output will be shutdown and both status outputs will be set. The
switch can only be activated again if the corresponding input is switched off and then on again. If
the output voltage does not exide 4.1 V, the output is not shutdown and the status outputs are not
set, although an overload may occur. The switches 5 and 6 are protected through a SOA-circuit. It
is suppressed for at least 10 µ s when the switch is turned on before it can start limiting the overload
current. The status outputs also monitor openload or shorted load to ground at the switches 5 and
6 in deactivated mode.
An analog signal is applied to the analog status output only when protection function is active. If
several malfunctions appear coincident, the highest voltage level of the analog status output will
dominate. Simultaniously the digital status output will be set.
The IC is also protected against thermal overload. If a chip temperature of typically 155 °C is
attained, the status outputs monitor overtemperature. If the temperature continues to increase, the
inputs and outputs of the switches 5 and 6 are shutdown. The switches 1 to 4 will not shutdown, so
precaution has to be taken in the application to prevent a further increase of the chiptemperature,
which may destroy the IC. After cooling down below 140 °C the overtemperature monitoring will be
reseted and the outputs of the switches 5 and 6 can be activated again.
If the minimum supply voltage for operation is not maintained, the outputs are deactivated. At a
supply voltage of higher than 1.8 V, the outputs 1 to 4 are switched on, if pin 14 (PREFST) is
connected to ground over a resistance smaller 1 M Ω . The outputs 1 to 4 can be controlled via the
inputs, if pin 14 (PREFST) is switched to high or not connected. Characteristics may be beyond the
specified values. Full function is guaranteed in the supply voltage range of 5 V ± 5 %.
Data Sheet
5
2002-10-21