Bipolar integrated device having parasitic current detector

摘要

A bipolar semiconductor integrated circuit for driving a motor and the like wherein a semiconductor pattern and a circuit are so contrived that an erroneous operation will not take place even when a negative potential is applied to the output terminal of the circuit. When a negative potential is applied, there exists a quantitative proportional relationship between a parasitic current of a parasitic transistor and a ratio of the lengths of the collectors. The parasitic current decreases with a decrease in the length of the collector. Therefore, the short side of a transistor in the control circuit is directed to the output transistor to which a negative potential will be applied. By detecting the parasitic current and by adding a current to the constant-current using a current mirror circuit, furthermore, erroneous operation due to parasitism can be completely prevented.