PURPOSE: To enhance the response of a drive circuit for thermal head by controlling voltage drop by lowering the internal resistance by a method in which two or more field-effect transistors are provided to a switching circuit, and a drive circuit is provided with paired transistors connected in a totem-pole form to supply the gate charge current of the field-effect transistors.
CONSTITUTION: The first common electrode C1 is connected in common to the drain of three field-effect transistors 31W33 in a switching circuit 21. Output voltage V0 is applied to the source, where resistors 34W36 are each connected to the gate and the other end of these is connected with the output terminal of a drive circuit 11. The drive circuit 11 is provided with a field-effect transistor 44 to receive control signals 43 and complementary paired field-effect transistors 45 and 46 connected in a totem-pole form, which is provided in the following stage and to be used frequently in the output circuit of TTL. Since the internal resistance of the switching circuit and the impedance of the drive circuit are low, high-speed switching can be made possible.
YAMAMOTO TADASHI
INUI TETSUYUKI
