It sounds like you're looking for a laptop charger with specific power output: 20V at 4.5A (90W). This type of charger typically comes with a USB   a proprietary Lenovo charging pin, depending on the laptop model.

Here’s what you need to know:

1. Power Requirements: A 20V 4.5A charger provides 90W of power, which is suitable for many Lenovo laptops, including some models in the ThinkPad and Legion series. Always check your laptop’s specifications to ensure the charger provides the right wattage and voltage.

2. Official Charger vs. Third-Party: If you're purchasing a charger, you can either buy an official Lenovo charger or a third-party one that’s compatible. When choosing a third-party charger, make sure it supports the correct voltage (20V) and amperage (4.5A) for your model. It’s often safest to use the official charger, as this ensures compatibility and reduces the risk of damage to your laptop.