Can a battery charger be qualified as an IC current limiter under clause G.9?
More specifically you asked: Can a battery charger be qualified as an IC current limiter under clause G.9 - i.e., can a whole battery charger circuit (including all the discrete electronic components) be considered as an IC current limiter and can this circuit can be tested according to G.9?
In response, first, we will have to assume that the battery charger you mentioned is the IC controller and related discrete components to control the charging voltage / current to a downstream device with batteries. The following answer is based on this assumption.
Sub-clause G.9, Integrated circuit (IC) current limiters, is only suitable for single semiconductor devices (containing numerous integral components) and not for discrete electronic components that may comprise of a circuit that also provides current limiting. Since fault testing cannot be applied inside the semiconductor devices, except on the external IC pins, in order to assess the reliable performance / function of the IC, the 62368-1 standard has a performance-based test program (G.9) for IC current limiters to verify the reliable performance / function.
However, for other circuits consisting of discrete electronic components, the reliability of whole circuit to perform a safeguard function can be determined by single fault testing. Therefore, single fault tests typically are conducted on selected components to verify the performance / function of this circuit to act as a safeguard, such as if it is being used to meet the requirements in sub-clause Q.1, Limited power source, in Annex Q, which requires that if a regulating network is limiting the output, simulated single faults are conducted within the regulating network. Therefore, for circuits with discrete electronic components, compliance with sub-clause Q.1 in Annex Q is appropriate and not sub-clause G.9.
However, we suggest you contact UL to discuss the details of your specific application since the information provided was limited, and compliance can depend on the details associated with a specific construction or product.