Low-power Y-capacitor-free power adapter

The utility model discloses a low-power Y-capacitor-free power adapter, which comprises a transformer connected between an alternating current power supply and a load, and the transformer comprises an Np winding, a Naux winding, an SH winding and an Ns winding which are sequentially wound from inside to outside, and the functional parameters of the transformer are improved by setting the single-layer turn ratio of the Naux winding to the SH winding and the density of the drop wire. Compared with the prior art, the utility model breaks through the dependency relationship between EMI and the Y capacitor, and avoids the problems of overlarge input and output leakage current and overlarge voice interference when a user uses an adapter with the Y capacitor. 本实用新型公开了一种小功率无Y电容的电源适配器，其包括连接于交流电源与负载之间的变压器，所述变压器包括从内向外依次绕制的Np绕组、Naux绕组、SH绕组和Ns绕组，并通过设置所述Naux绕组与SH绕组的单层匝数比和落线疏密程度提升所述变压器的功能参数。与现有技术相比，本实用新型突破了EMI与Y电容之间的依赖关系，避免了用户使用加Y电容的适配器存在输入和输出漏电流过大、语音干扰过大的问题。