Abstract: A vacuum switching valve and a suction system having the same. The vacuum switching valve comprises: a valve body, comprising a first end and a second end, the second end being provided with an air inlet, an air outlet and a through hole; a valve element movably arranged in the valve body; a cylinder, the cylinder being connected to the first end and the valve element, the cylinder drives the valve element to move in the valve body, to close or open the air inlet; a stopper passing through the through hole, the stopper comprising a third end and a fourth end, the third end being connected to the valve element, the fourth end being located on the side of the through hole away from the valve element.

Abstract: An SRAM and a forming method and a controlling method thereof are provided. The above-mentioned SRAM includes a tracking column, a normal column, a cell voltage control circuit and a cell voltage pull-down circuit. Each of the tracking column and the normal column includes a plurality of memory cells. The cell voltage control circuit is coupled to the tracking column and the normal column for connecting an operation voltage to the two columns before a write operation of the SRAM starts and for disconnecting the operation voltage from the two columns after the write operation starts. The cell voltage pull-down circuit is coupled to the two columns for pulling down the cell voltages of the two columns after the write operation starts and for ceasing pulling down the cell voltage of the normal column when the cell voltage of the tracking column drops down to a predetermined voltage.

Abstract: An SRAM and a forming method and a controlling method thereof are provided. The above-mentioned SRAM includes a tracking column, a normal column, a cell voltage control circuit and a cell voltage pull-down circuit. Each of the tracking column and the normal column includes a plurality of memory cells. The cell voltage control circuit is coupled to the tracking column and the normal column for connecting an operation voltage to the two columns before a write operation of the SRAM starts and for disconnecting the operation voltage from the two columns after the write operation starts. The cell voltage pull-down circuit is coupled to the two columns for pulling down the cell voltages of the two columns after the write operation starts and for ceasing pulling down the cell voltage of the normal column when the cell voltage of the tracking column drops down to a predetermined voltage.