| 摘要 |
<p>PROBLEM TO BE SOLVED: To eliminate a 1/2 frequency-dividing circuit, which is required for securing 50% of a duty ratio, and to prevent jitter from deteriorating by setting the duty ratio to be 50% at the stage of source oscillation without depending on an oscillation frequency. SOLUTION: When the signal at a high level is outputted from a buffer 18, a switching element 15 grounds the gate of the MOSFET 16 and a switching element 19 inputs reference voltage VA to the terminal (+) of a comparator 17. The MOSFET 16 is turned off and a capacitor 14 is charged. When the voltage of the capacitor 14 becomes higher than reference voltage VA, the signal at the low level is outputted from the comparator 17 and the signal at the low level is outputted from the buffer 18. Furthermore, the switching element 15 is grounded to the gate of the MOSFET 11 and the switching element 19 inputs reference voltage VB to the terminal (+) of the comparator 17. Thus, both periods of the high and low levels become equal and the duty ratio becomes 50%.</p> |
