Overcurrent protection circuit applied to LDO
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The utility model discloses an overcurrent protection circuit applied to an LDO. The overcurrent protection circuit comprises an LDO chip, an MOS tube M1, an MOS tube M2, an MOS tube M3, an MOS tube M4, an MOS tube M5, an MOS tube M6, an MOS tube M7, an MOS tube M8, an MOS tube M9, an MOS tube MP1, an MOS tube MP2, a safety resistor R1, a safety resistor R2, a safety resistor RF1 and a safety resistor RF2. The output end of the LDO chip is connected with the grid electrodes of the MOS tube MP1, the MOS tube M1, the MOS tube M2, the MOS tube M3 and the MOS tube M4 and the drain electrode of the MOS tube MP2. The drain electrode of the MOS tube M1 is connected with the source electrode of the MOS tube M2, the drain electrode of the MOS tube M2 is connected with the source electrode of the MOS tube M3, the drain electrode of the MOS tube M3 is connected with the source electrode of the MOS tube M4, the drain electrode of the MOS tube M4 is connected with the source electrode of the MOS tube M5, the grid electrode of the MOS tube M5, the grid electrode of the MOS tube M8, the source electrode of the MOS tube M8 and the drain electrode of the MOS tube M7 are connected, and the other end of the safety resistor RF1 is connected with the safety resistor RF2 and the feedback input negative electrode of the LDO chip. The overcurrent protection circuit has the advantages that when the current of a power adjusting tube increases and reaches a certain fixed value, the MOS tubes connected with the LDO output end are opened, the current at the output end is extracted, the current of a feedback branch circuit is prevented from being too large, and the purpose of overcurrent protection is achieved.