Patent ID: 7477493

Claim:
A control device for a vehicle alternator, comprising: a first external terminal that receives a rectified output of the vehicle alternator or supply of output from a battery charged by the rectified output; a second external terminal connected to a field coil of the vehicle alternator; a third external terminal to which a phase voltage of the vehicle alternator is input; at least one forth external terminal that is connectable to an external device; and an excitation control portion that controls an exciting current that flows in the field coil, the control device for the vehicle alternator performing control using a load response function that controls the excitation control portion to control the output of the vehicle alternator, and further comprising: a specified signal detection portion that detects when a specified signal is applied to at least one of the first to the fourth external terminals; and a load response coefficient switching portion that switches a value of a load response coefficient of the load response function when the specified signal detection portion detects the specified signal.