Micro-current amplifier

The invention provides a micro-current amplifier, which comprises a bias circuit, a speed boosting circuit and a current amplifying circuit, the bias circuit comprises at least one group of first PMOS (P-channel Metal Oxide Semiconductor) transistors, the first PMOS transistors comprise a PMOS transistor M1 and a PMOS transistor M2, the drain electrode of the PMOS transistor M1 is electrically connected with the source electrode of the PMOS transistor M2, the gate electrode of the PMOS transistor M1 is electrically connected with the drain electrode of the PMOS transistor M2, and the current amplifying circuit is electrically connected with the speed boosting circuit. The gate electrode of the PMOS tube M2 is electrically connected with a current input end, the drain electrode of the PMOS tube M2 is electrically connected with the current input end through a resistor R6, the speed increasing circuit comprises at least one group of second PMOS tubes, the second PMOS tubes comprise a PMOS tube M3 and a PMOS tub