Torque-control circuit for electric motor of hand tool e.g. screwdriver, has torque configuration circuit connected with reference voltage generator circuit, such that reference voltage is generated corresponding to desired torque level

摘要

The circuit has a motor drive circuit (1) connected with an electric motor (10), and a current detection circuit (2) connected in series with the drive circuit. A current limiting circuit (4) has an input terminal that is connected with a connection point between the drive circuit and the detection circuit. A reference voltage generator circuit (3) supplies reference voltage to an input terminal of the limiting circuit. A torque configuration circuit (5) is connected with the generator circuit, such that the reference voltage is generated corresponding to a desired torque level.