🔌 Lenovo Square Tip 20V Power Adapter. 20V – 3.25A → 20 × 3.25 =65W. For example, if your laptop requires20V 3.25A (65W), you can safely use a20V 4.5A (90W) adapter. All adapters listed here use theLenovo square tip (yellow tip) connector and provide20V output.