| 摘要 |
Depending on the desired direction of current flux through an electrical load such as a stepped motor, in a measuring bridge circuit provided with switchable semiconductors and recovery diodes the semiconductors through which the current direction is switched are closed, causing the actual current to increase until it has attained the nominal current value, whereupon switching is effected into either slow current decay mode or fast current decay mode. A selection of the operating mode is made at the next semiconductor switch-on such that, if the actual current value is greater than the nominal current value at the next semiconductor switch-off, fast current decay mode is selected, and if the actual current value is lower than the nominal current value, slow current decay mode is selected. For the remainder of the chopper period, for example until the next switch-on, the operating mode is no longer changed, or switching is effected once from fast current decay mode into slow current decay mode, as a function of a comparator device that compares actual current values and nominal current values, if the actual current value is lower than the nominal current value. The invention can be used in actuation electronics for stepped motors.
|
