LT1375 voltage drops to 50mV when converting 19V resonator output to 5V USB 1A

A user attempts to build a power supply using a resonator circuit providing 19 V DC at 8 W (with a 43 Ω load) to charge a phone requiring 5 V at 1 A. The user employs an LT1375 buck converter to step down from 19 V to 5 V but observes the output voltage dropping to 50 mV when connected to the resonator output. The LT1375 functions correctly in isolation, but the combined AC-DC resonator and DC-DC converter setup fails to deliver the expected output. Responses suggest the input voltage from the resonator circuit sags under load, insufficient for the LT1375 to regulate properly. Increasing the resonator input voltage from 30 V to 40 V in simulation yields the desired 5 V, 1 A output. Alternative converter topologies such as SEPIC or buck-boost converters are recommended to handle input voltages both above and below the output voltage. The presence of a bridge rectifier without an AC supply and the resonator system's complexity are also noted as potential issues.
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