| 摘要 |
PURPOSE:To obtain a constant-voltage output for a wide range of input voltage, by conducting a frequency control of a pulse-width signal according to the voltage of an input signal. CONSTITUTION:Since the change in an input voltage Vin is substantially equal to the change in the wavelength value of E1, the wavelength value is read by a peak hold circuit 18, and by the output of this circuit, the resistance value RT of a variable resistance element 16 is controlled for controlling frequency. RT may be controlled roughly, and it is required only to switch the resistance value RT by a switching means, because the final precision of an output voltage V0 is dependent on the control of a pulse width. Since the output voltage is maintained at a constant value by a frequency control corresponding to the change in the input voltage Vin in this way, a constant-voltage output can be obtained for a wide range of input voltage. |
