OVER CURRENT PROTECTION CIRCUIT IN LOW DROP OUTPUT REGULATOR

摘要

The present invention detects that an overcurrent is flowing to the output terminal of the low voltage regulator to block the flow of the over-current relates to a technique. The present invention, by-pass to the input voltage supplied to the power supply output terminal but substituting an input terminal, under the control of the output voltage of the differential amplifier is supplied to the gate of the bypass transistor so that the voltage of the power supply output terminal held at a constant voltage and; And the divided portion of the divided voltage at a predetermined ratio by using a resistor voltage divider for the output of the power supply output terminal; Comparing the reference voltage and a predetermined voltage divided parts of the output voltage, supplies the difference voltage to the gate of the bypass transistor and the differential amplifier such that the output voltage is bypassed to the power supply output terminal held at a constant level; And the over-current detection unit for outputting a detection signal corresponding thereto to detect the over-current is flowing through the power output terminal; Overcurrent detection signal output unit for outputting a normal extending the current detection signal and the overcurrent detection signal output when a predetermined time delay, the overcurrent is detected again after a normal current detected by the overcurrent detecting unit; The over-current detection signal extending over-voltage output of the power output stage to turn off the by-pass character transistor while the elongated over-current detection signal is output from the output unit is achieved by the over-current blockers fisherman to be cut off.