L7800 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'L7800' PDF : 29 Pages View PDF
Figure 33 : Protection against Input Short-Circuit with High Capacitance Loads
L7800 SERIES
Application with high capacitance loads and an output voltage greater than 6 volts need an external diode (see fig. 33) to protect the device
against input short circuit. In this case the input voltage falls rapidly while the output voltage decrease slowly. The capacitance discharges by
means of the Base-Emitter junction of the series pass transistor in the regulator. If the energy is sufficiently high, the transistor may be de-
stroyed. The external diode by-passes the current from the IC to ground.
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