| 摘要 |
PURPOSE:To provide a small-sized and inexpensive voltage generator which can obtain the output voltage having a stable and accurate value. CONSTITUTION:A capacitor C connected in series to a capacitive load is charged by a voltage supply means, which includes a transistor TR Tr1 driven by a PWM signal having a pulse width tUP(n), in the period of output voltage increase and is discharged by a discharging means, which includes a TR Tr2 driven by a PWM signal having a pulse width tDN(n), in the period of output voltage reduction, thus obtaining a desired output voltage waveform. In this case, tUP(n) and tDN(n) are equal to alpha(V(n)-V)+tUP(n-1) and beta(V-V(n)) where alpha and beta are proportional constants and V(n) is the output voltage of the next target and V is the detected output voltage and (n) is the frequency in sampling counted till then in a single period of the output voltage. |
