| 摘要 |
PURPOSE:To stabilize the output of a power supply circuit and to prevent assuredly the quality deterioration of a minute music signal, by supplying the output of an auxiliary DC power supply to a smoothing capacitor for a prescribed period of time when the sudden reduction of the music signal level is detected. CONSTITUTION:When the level of the music signal outputted from an amplifier 4 is reduced suddenly, a mirror detecting circuit 10 works to produce an impulsive output. This pulse triggers a one-shot multi circuit 11 to produce the output signals for a prescribed period (t). Thus a transistor Tr 12 is turned on and the output of the Tr 12 turns on a Tr 13. Then a charging current is supplied to a smoothing capacity 3 from a capacity 9 serving as an auxiliary DC power supply 15. As a result, the current supplied from the capacitor 9 is supplied instantaneously to the capacitor 3 having shortage of the charging amount immediately after the music signal of a high level is treated by the amplifier 4. Thus, the power supply output is stabilized, therefore the effects to the music signal is prevented. |
