A comparator-based switched-capacitor circuit has a first output terminal and a second output terminal, and includes a switch-capacitor network, a first current source, and a second current source. Each of the first current source and the second current source includes a first transistor, a second transistor, a capacitor, and a buffer circuit. The first transistor has a first source, a first drain, and a first gate. The first drain is coupled to the first output terminal, the first source is coupled to a reference voltage, and the first gate is coupled to the switch-capacitor network. The second transistor has a second source, a second drain, and a second gate. The second source is coupled to the first output terminal. The capacitor is coupled between the second gate and the second source. The buffer circuit is coupled between the second source and the second drain.