| 摘要 |
PROBLEM TO BE SOLVED: To provide a comparator that can directly compare a high input voltage in a simple configuration without damaging MOS-FETs with a thin gate oxide film.SOLUTION: The comparator includes: a differential amplification type comparator body including a pair of input MOS-FETs for differentially receiving a reference voltage and an input voltage, a pair of load MOS-FETs on the input MOS-FETs which have gates connected together, and a constant current source for supplying a constant current to sources of the input MOS-FETs; and specifically Zener diodes connected in parallel between gates and sources of the input MOS-FETs, respectively, which have a breakdown voltage characteristic equal to or lower than a withstanding voltage of a gate oxide film of the input MOS-FETs. A feedback MOS-FET is also disposed for negatively feeding an output voltage of the comparator body back to the gates of the load MOS-FETs to limit the amplitude of the output voltage. Semiconductor rectifying elements having a reverse-blocking characteristic equal to or higher than a supply voltage are furthermore interposed between the constant current source and the drains of the input MOS-FETs, respectively. |
