Contrary to popular belief, "Xin Zhi Zhao" is not a single, ubiquitous chip like the LM317 or NE555. Instead, it is a specific series of power management ICs (PMICs) and battery protection circuits originating from Chinese semiconductor manufacturers, often found in low-cost Bluetooth speakers, power banks, e-cigarettes, and LED flashlights.
Xin Zhi Zhao supports an extensive range of brands and device types: xin zhi zhao schematic