原理图如上,在轻载约60mA下,输出电压会在启动一段时间后从2.2V左右变为3.6V并稳定,VFB基准电压也从0.76V左右上升到0.8V,此时SW无方波波形。有尝试修改输出电感、电容,均无明显效果。增加负载至70mA左右输出回复正常。
是否轻载导致输出电压异常?
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Hi
建议你按照datasheet推荐输入输出都用陶瓷电容,而你选择的电解电容,可能导致控制的不稳定。
或者你用在线仿真webench确认一下电路。