Hi,
well ... its a kind of odd question. Since you already know that its used on a HP switch (you might want to persue the knowledge you're asking from the source who gave you that information).
Otherwise -
BCM56150:
is a 24-Port Managed GbE Switch with Four 10GbE Uplinks, Integrated CPU, and 16 Copper PHYs
pretty handy SoC, and you probably want to look for 24 port switches with 4 10gig uplinks. Might want to look for a model where the ports are divided in sections of 8?
BCM54282 is a Octal-Port QSGMII Copper Gigabit Ethernet Transceiver, might be used in conjunction with BCM56150 to make all 24 ports copper PHYs...
BCM59121 is not on www.broadcom.com, but
BCM59111 is a Quad Integrated IEEE 802.3at-Compliant PSE Controller
that is PoE.
So, if you have a switch with all 3 chipsets inside, I'd look for a 24 port copper GbE PoE(+), with 4 10GbE uplinks.
maybe something like the HP 5130-24
Regards