| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve the control characteristic and noise immunity of a system employing the pulse width modulation control circuit by keeping a peak voltage of an outputted triangle wave constant even when a frequency of a synchronizing signal (synchronizing frequency) is subjected to change. SOLUTION: The circuit is provided with a triangle wave oscillation section 101 generating a triangle wave based on a synchronizing signal, and a triangle wave control section 200 that receives a triangle wave voltage VTR generated by the triangle wave oscillation section 101 as its feedback input and also a reference voltage VTref with respect to the triangle wave voltage VTR and provides an output of a control current ICH to the triangle wave oscillation section 100 so that the peak level of the triangle wave VTR is constant, and also with a pulse width modulation section 300 that receives an output voltage VO being a controlled object and a reference voltage VOref with respect to the output voltage VO and the triangle wave voltage VTR generated from the triangle wave oscillation section 100, modulates the pulse width of the output voltage VO being the controlled object and provides as output.</p> |
