| 摘要 |
PROBLEM TO BE SOLVED: To eliminate A/D conversion and the processing time required for comparative operation so as to raise the control speed, by comparing the load current detection voltage with objective voltage, and reading in the output with a microcomputer, and deciding the direction of control of the output voltage of a power source by its polarity. SOLUTION: The output of a comparator 26 is connected to the input terminal of a microcomputer 17. CPU 19 reads in the output of the comparator 26 through an i/o control circuit 24, and in the case that the output of the comparator 26 is Hi, it transmits the data for lowering the duty ratio of output pulses to a PWM pulse control circuit 23, judging that the tube current is large. Conversely, in the case that the output of the comparator 26 is Lo, it transmits the data for raising the duty ratio of the output pulse to the PWM control circuit 23, judging that the tube current is little. Hereby, the microcomputer 17 need not perform A/ID conversion or comparison of digital values, and the processing of the microcmputer 17 can be reduced, and the control speed improves. |
