| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent an uneven print density by controlling a variation in reference voltage caused by a variation in power-supply voltage and eliminating a variation in driving current. <P>SOLUTION: A reference voltage generation circuit 60 drives NPNTR 65 and 66 by using a current mirror circuit part 61 which is made up by cascade connection between a first current mirror circuit comprising PMOS 61a and 61b and a second current mirror circuit comprising NMOS 61c and 61d. Therefore, a node N3 and a node N4 which are on the output side of the current mirror circuit part 61 have an approximately equal voltage. As a result of this, even if a value of power-supply voltage VDD varies, it is possible to minimize a variation in collector voltage of NPNTR 66, and to reduce a variation in reference voltage Vref output from the reference voltage generation circuit 60 to a negligible level. <P>COPYRIGHT: (C)2012,JPO&INPIT |
