How does using ASIC for the acceleration of AI work? We can read on Wikipedia page that Google built a custom ASIC chip for machine learning and tailored for TensorFlow which helps to accelerate AI.

Since ASIC chips are specially customized for one particular use without the ability to change its circuit, there must be some fixed algorithm which is invoked.

So how exactly does the acceleration of AI using ASIC chips work if its algorithm cannot be changed? Which part of it is exactly accelerating?
Tensor operations

The major work in most ML applications is simply a set of (very large) tensor operations e.g. matrix multiplication. You can do that easily in an ASIC, and all the other algorithms can just run on top of that.