| 摘要 |
PROBLEM TO BE SOLVED: To hold the through current of a buffer circuit, which outputs a logic signal to the outside, within a specific range even if the ambient temperature varies. SOLUTION: The output buffer circuit 11 which leads a logic output out from an output terminal 19 is constituted by connecting multiple output circuits in parallel. A switch (SW) control circuit 12 controls a combination of output circuits which are activated among the output circuits according to an on- resistance of a CMOS inverter circuit of an output circuit to be simulated by a resistance 14. The SW control circuit 12 converts the voltage, generated by supplying a constant current from a constant current circuit 15 to the resistance 14, into a digital value by an analog-digital converting circuit 13 and according to the converted digital value, CMOS inverter circuits which are selected by the SW control circuit 12 are activated to control the on-resistance of the whole output buffer circuit 11 within a specific range.
|
