Large aperture plasma electrode Pockels cell (PEPC) is the key unit of the multi-pass amplified scheme of SGⅡ upgrading laser. The PEPC in this scheme should achieve the status switching between on and off in a very short time. The response time of the PEPC driven by positive-negative switching pulses is not as short as the demand of the multi-pass amplified scheme. In the single-pulse process, the low-impedance high voltage generator based on Blumlein pulse-forming line is used to drive the PEPC, and the response time can be reduced greatly. The theoretical charge time of the plasma switch with 350 mm×350 mm aperture is about 54 ns, and the response time can be less than 90 ns in single-pulse process. The experimental results of the switching efficiency of full aperture are higher than 99.7%. The extinction rate exceeds 381. The top width of the time window is larger than 160 ns, and the bottom width is less than 400 ns. All these experimental results can meet the specification of SGⅡ upgrading laser.