Circuit Diagnosing Apparatus and Battery Pack Including the Same

A circuit diagnosing apparatus for diagnosing a battery pack including a battery cell and a main relay connected in series, the circuit diagnosing apparatus comprising:

• a control unit configured to output a first signal of a preset duty cycle through a first line connected to the main relay;
• and
• a DC-DC converter, connected to the first line, configured to:
• receive the first signal through the first line;
• receive a second signal output from the battery cell in response to the first signal changing an operation state of the main relay to a turn-on state;
• convert the first signal and the second signal;
• and
• transmit a first conversion signal and a second conversion signal obtained by the conversion to the control unit;
• wherein the control unit is configured to:
• receive the first conversion signal and the second conversion signal from the DC-DC converter;
• determine whether the first conversion signal and the second conversion signal include one or more common signal properties;
• and
• determine whether the battery pack has a defect based on the determination of whether the first conversion signal and the second conversion signal include one or more common signal properties.