| 摘要 |
<p>PURPOSE: To reduce the noise of a CMOS driver and to guarantee a high output level by providing a voltage and current limiter means between the power supply voltage and the first current electrode of a pull-up PMOS transistor. CONSTITUTION: When an output node N3 transits to a high output, a PMOS transistor PM and an NMOS transistor NM are instantaneously and simultaneously turned on and a peak current flows to a grounding conductor from a power supply voltage line. When the peak current flows, the current is limited to a diode forward current ID by means of a P-N junction diode D. In addition, a voltage which is obtained by subtracting a forward voltage drop VD from the power supply voltage VCC, namely, VCC-VD is applied across an output node N3 from the diode D. Therefore, the noise VN which is produced from the power supply voltage line and grounding conductor when data are outputted is reduced by the ratio (VCC-VD)/VCC because the noise VN is in proportion to the swinging width V of the voltage.</p> |
