Power window driving device

#The present invention relates to a power window driving device for controlling a power window provided in a vehicle and more particularly to the art of preventing the misreversing of a power window while the vehicle provided with the power window driving device drives on a rough and bumpy road.

#The window glass of power windows mounted on the vehicle is connected to a drive motor and by throwing switches reversibly to rotate the drive motors, the window glasses move upward or downward. Moreover, some power window that has been proposed and put to practical use functions as what prevents damage to not only the obstacle caught in the power window but also the power window itself while the window glass is moving upward by stopping the drive motor and further reversing the rotating direction of the drive motor so as to move the window glass downward.

#With such a related power window driving device, the art of suspending the operation of and reversing direction of the drive motor is disclosed in JP-A-10-25964 (FIG. 1) in which a driving device is suspended and reversed when an obstacle is so pinched in the power window that an increase of the electric current flowing through the drive motor exceeds a predetermined level.

#The above objects and advantages of the present invention will become more apparent by describing in detail preferred exemplary embodiments thereof with reference to the accompanying drawings, wherein:

#FIG. 1 is a block diagram showing the construction of a power window driving device according to a first embodiment of the invention;

#FIG. 2 is a circuit diagram showing the construction of the power window driving device according to the first embodiment of the invention.

#The embodiments of the present invention will be described with reference to attached figures. FIG. 1 shows a power window driving device according to the invention; and FIG. 2 shows a detailed circuit diagram according to the invention.

#As shown in FIG. 1, a power window driving device 100 according to the invention is provided in the interior of a vehicle and used for moving up and down the window glass of a power window provided therein. The power window driving device 100 includes a motor driving circuit including a drive motor M1, a reference-current generating circuit 2 for generating a current Ir (=Ir1+Ir3; reference current) proportional in size to a current ID flowing into the drive motor M1, a reference-voltage generating circuit 5 for detecting the size of a change in the reference current, and a rough road detection circuit 3 for detecting a pulsating component, if any, in the current ID in predetermined frequency bands (ranging approximately from 10 to 15 Hz) so as to decide that the vehicle is traveling on a rough road. For example, the current Ir is approximately {fraction (1/15000)} of ID in size.

#Further, the power window driving device 100 includes a comparator CMP1 for comparing a voltage Vins (a comparison signal) corresponding to a variable quantity of the current ID flowing into the motor driving circuit 1 with a predetermined reference voltage Vc (reference level) so as to output a decision signal according to the result of comparison, and an inverting control circuit 4 for reversing the rotating direction of the drive motor M1 in the motor driving circuit 1 when the comparator CMP1 detects that a steep increase of the current ID flowing into the motor driving circuit 1 exceeds a level based on the reference voltage Vc and when the continuation of the increase of the current ID exceeds a predetermined time.