| 摘要 |
PROBLEM TO BE SOLVED: To omit A/D and D/A conversion in a microcomputer. SOLUTION: The functions of a microcomputer 27 are limited to the selection of a specific segment and the designation of a sampling interval synchronized to the selection. In a sampling period, a driving current I is given to a specific segment and a stabilized power supply Vout is optimized so that the current I becomes constant by a control loop made up with a current detecting circuit 25, a current value sample-and-hold circuit 26, a driving voltage controlling circuit 24 and a driving voltage control element 22. In a voltage hold period, a voltage specifying value held in a hold capacitor C1 of the circuit 26 in the sampling period is given to the circuit 24 and the element 22 holds the optimized stable power supply Vout in accordance with the above operations. |
