Patent ID: 8829956
Filing Date: 2014-09-09
Classification: H03K

Abstract:
1. A signal generating circuit for generating a fan driving signal, the signal generating circuit comprising: a phase adjusting circuit, receiving a hall signal and adjusting a phase of the hall signal to generate a synchronization signal; a direct digital frequency synthesizer, coupled to the phase adjusting circuit and generating a modulating signal according to the synchronization signal; a first operating circuit, receiving a load current and generating a modulated signal according to the load current; a driving signal generator, coupled to the phase adjusting circuit and generating an original driving signal according to the synchronization signal; and a second operating circuit, coupled to the first operating circuit, the direct digital frequency synthesizer and the driving signal generator and generating a control signal according to the modulating signal and the modulated signal, wherein the original driving signal is selectively outputted as the fan driving signal in response to the control signal.