| 摘要 |
<p>PURPOSE:To prevent a mutual electrical interference in a grounding line by each separating a MOS logic circuit and a grounding wiring for an output transistor and mounting the logic circuit and a terminal for the grounding wiring for the output transistor mutually independently. CONSTITUTION:When a power supply is turned ON, a logic control signal generated from a MOS logic circuit 1 is transmitted selectively over each output transistor 3. Currents are applied to each thermal-head heating element 7 in response to the ON states of several output transistor 3. A grounding terminal G2 for the output transistors and a grounding terminal G1 for the logic circuit 1 are not directly in contact mutually on an IC chip 5a and each becomes independent at that time. Consequently, the grounding terminal G1 for the logic circuit is left as it is kept at a grounding level even when large currents flow through the output transistors. Accordingly, stable operation is obtained at substrate potential at the determined grounding level of the logic circuit 1, and the switching operation of the stable output transistor in which there is no malfunction is acquired.</p> |
