| 摘要 |
To control the current through a winding interconnected in an H-bridge to control e.g. a stepping motor, at the beginning of each chopper period, the H-bridge is kept in its slow demagnetization state during predetermined interval (t1-t2). Then, just before, at or just after the end of that interval, the actual current value (IA) is compared with a desired value (ID). If the actual value (IA) is smaller, the H-bridge is kept in its magnetization state, at the most until the end of the chopper period. If the actual value is larger, the H-bridge is kept in its fast demagnetization state, at the most until the end of the chopper period. Hereby, the current is regulated to the desired value with a minimum of current ripple. This reduces the electromagnetic radiation. Also, the impact of current spikes, appearing when the H-bridge is switched, is brought to a minimum. |
