ir2113S驱动设计

我用IR2113S驱动逆变电源的IGBT,在没上直流高压时,四路IGBT驱动波形都正常的,用直流电源加入到直流高压处,从0V开始加,发现上臂两个驱动波形的电压在根随直流电压上升而上升.这是为什么?附波形500) {this.resized=true; this.width=500; this.alt='这是一张缩略图，点击可放大。\n按住CTRL，滚动鼠标滚轮可自由缩放';this.style.cursor='hand'}" onclick="if(!this.resized) {return true;} else {window.open('http://u.dianyuan.com/bbs/u/40/1144465594.gif');}" onmousewheel="return imgzoom(this);">500) {this.resized=true; this.width=500; this.alt='这是一张缩略图，点击可放大。\n按住CTRL，滚动鼠标滚轮可自由缩放';this.style.cursor='hand'}" onclick="if(!this.resized) {return true;} else {window.open('http://u.dianyuan.com/bbs/u/40/1144465608.gif');}" onmousewheel="return imgzoom(this);">