Switch-mode converter power supply, uses resonant elements with element voltage being compared with threshold during pre-switching zero-voltage phase, to assess inductive or capacitive load connection

摘要

The inventive circuitry includes an assembly (5), outputting voltage (U2) to load, and containing resonant elements (Cr, Lr), used for processing DC voltage (U3), derived by chopping input voltage (U1) with resonant circuit elements (S1, S2), which have alternating switch-on phases. In order to monitor a connected load, before elements (S1,S2) are switched on, applied voltages (US1) or (US2) are compared during a zero-voltage phase with a threshold, to determine whether a connected load is inductive or capacitive. In an alternative embodiment, the differentials of voltages (US1,US2) are compared with a predetermined value to assess whether the load is inductive or capacitive.