Flex Ltd.
Adaptive resonant frequency converter

Abstract:

A resonant power converter has a main switch, a resonant tank coupled across the main switch, and a signal processing circuit coupled to the main switch and the resonant tank. The signal processing circuit generates a driving signal for driving the main switch ON and OFF at a switching frequency. The resonant tank includes circuit components designed to have a resonant frequency that is tuned to a designed switching frequency of the main switch. The signal processing circuit includes a zero voltage switching (ZVS) circuit, a signal generator, a detection circuit, and a latch oscillator. The signal processing circuit is configured to adjust the switching frequency of the driving signal to be tuned to the actual resonant frequency of a resonant tank under very high switching frequency conditions, 1 MHz and greater, thereby accounting for the influence of parasitics at very high switching frequencies and achieving resonance of the circuit.