Abstract: Method for operating a DC motor where the DC motor is supplied with a variable DC voltage via a bridge circuit from a supply voltage and formed by a first, a second, a third and a fourth controllable switch, wherein the DC voltage is varied by pulse width modulation of the control signals driving the controllable switches of the bridge circuit. A control arrangement drives the bridge circuit by pulse width modulation, after the first switch connecting the DC motor to the supply voltage has been switched off, switches on the second switch connected to a ground terminal, or vice versa. The control arrangement automatically inserts a drive pause between the first or second switch being switched off and the second or first switch being switched on, whereby a bridge circuit voltage present at the DC motor is limited by a resultant maximum settable duty cycle to a maximum value.

Abstract: A method for determining and specifying necessary closing speed of a motor-operated vehicle door at the moment of reaching an initial closure detent by means of a control unit is described. The motor current of the door motor is determined and compared with a calculated maximum current, wherein the maximum current results from a motor armature resistance measured at the start of the door movement, from a minimum supply voltage of the control unit and from an adjustable factor. If the determined current is higher than the maximum current, the value of an adaptation table is changed and a higher closing speed is specified by the control unit for the next closing movement of the vehicle door; and, if the determined current is lower than the maximum current, a lower closing speed is specified by the control unit for the next closing movement of the vehicle door.