| 摘要 |
PURPOSE:To obtain the double voltage having the positive and negative absolute values which are exactly equal to each other, by connecting a pair of batteries and two pairs of DC-DC converters, connecting in series the outputs of those two pairs of converters and comparing the middle point of said outputs with an earth potential. CONSTITUTION:A pair of batteries of voltage Vi are connected to DC-DC converters 3A and 3B. When the input voltage Vi is lower than 6V, for example, the voltage Vi emerges directly at a terminal T1. While if the Vi is higher than 6V, the pulse width is modulated 4 for the output of a comparator 5. Then a transistor TRQa is controlled, and the voltage VO is raised up to the reference voltage of 9V, for example. The converter 3B compares 7 the reference voltage with the potential at the joint of resistances r1 and r2 of the same value and modulates 6 the pulse width. The potential of a terminal TO is set at -VO by a TRQb. The difference of potentials is equal to 2VO between terminals T1 and T2. The voltage twice as high as power supply voltage E is applied to a power amplifying part 1 which supplies a signal (e), and therefore an output of 4-fold efficiency is obtained through a speaker SP. Thus it is possible to generate the double voltage and to use together different types of batteries. |
