Signal synchronizing device and digital signal output device

A signal synchronizing device, coupled to a digital circuit that generates an output voltage according to a first frequency signal, coupled to an analog circuit that generates a feedback signal according to the output voltage, comprising:

• a synchronization circuit, coupled to the analog circuit, sampling the feedback signal according to a second frequency to generate a synchronization signal;
• and
• a control circuit, coupled to the digital circuit and the synchronization circuit, generating a voltage control signal according to the second frequency signal and the synchronization signal to control the digital circuit to generate the output voltage, wherein the control circuit comprises:
• a first AND gate, wherein an output terminal of the first AND gate is coupled to the digital circuit;
• and
• a plurality of flip-flops, cascaded with each other and connected between an output terminal of the synchronization circuit and an input terminal of the first AND gate, sequentially transmitting the synchronization signal in response to the second frequency signal, wherein the input terminal of the first AND gate is coupled to an output terminal of each of the flip-flops and the output terminal of the synchronization circuit, and the voltage control signal is generated according to an output signal of each of the flip-flops and the synchronization signal, wherein a frequency of the first frequency signal is lower than a frequency of the second frequency signal, and the voltage control signal is synchronized with the feedback signal.