The invention relates to a choke circuit and a bus power supply incorporating same. Such a coil choke circuit includes an inductor connected between a first input terminal and a first output terminal, a boost circuit connected between a second input terminal and a second output terminal for increasing the voltage level that is output by the second output terminal. A switching element is connected in parallel to the boost circuit for bypassing the boost circuit. Additionally, a comparator is connected between the first input terminal and the first output terminal for detecting a potential difference across the inductor; wherein in case the comparator detects a potential difference higher than a threshold, the switching element is controlled to be in an OFF state; and in case the comparator detects a potential difference lower than or equal to the threshold, the switching element is controlled to be in an ON state.