(a) Unless the certificate of incorporation or a bylaw provides otherwise, regular meetings of the board of directors may be held without notice of the date, time, place or purpose of the meeting.
(b) Unless the certificate of incorporation or a bylaw provides for a longer or shorter period, special meetings of the board of directors shall be preceded by at least two days' notice of the date, time and place of the meeting. The notice need not describe the purpose of the special meeting unless required by the certificate of incorporation or bylaws.