I've encounter a Chinese patent from 1999 that mentions a battery charging IC named DP9902P-16. I cannot find any information on such a chip. From the schematic below, it appears to be a linear charging IC (16 below), likely with an I2C or SMBus interface to the battery. Any ideas what a DP9902P-16 is?

 

Its likely to be a proprietary chip only available to OEMs. Nothing comes up for that part # or similar. Dating from 1999 it obviously never became a mainstream part, or was marketed under a different part #.