Stability of SMPS designed for a motherboard
Are you asking about a SMPS that will power a variety of loads (motherboard of an air conditioner, mobile phone) without changing any of the design?

If so, I don't think such a design exists.

The closed loop performance of a power supply (PS) is closely tied to the load it has to drive and the resultant feedback that has to be implemented to ensure the power supply meets all it's performance requirements such as regulation, over current/over voltage protection, good behavior at startup, etc. Therefore most power supplies have to be tailored to their loads.

Our power supply group designs SMPS's for many different applications (loads). The design for a digital system with a relatively constant load is a lot different than the design for the transmit portion of a radar with hundreds of amps of load current being required at the radar's PRF (Pulse Repetition Frequency), 100 Hz to 50 kHz, for instance.