Yes, Canon at least shares the same chips between DSLR and smaller models. But one difference, is that the DSLRs often have multiple such chips in parallel, compared with a single chip in the compact models. This improves throughput, making the DSLR much faster.

My DSLR has 10 (or is it 12?) megapixels. So do many "compact" cameras. Given the sensor is massively larger in the DSLR, the pixels end up being much larger, and therefore more sensitive.

But even when comparing different pixel counts, the pixels in the DSLRs always end up being huge compared with the compact camera sensors.

Cheers