| 摘要 |
A peak hold circuit is provided that operates stably even if a peak voltage to be held of a motor-drive-current detection voltage is minute. The peak hold circuit includes: a level shift circuit shifting the motor-drive-current detection voltage by a given voltage; a differential amplifier circuit receiving an output voltage of the level shift circuit and a voltage at an output terminal to amplify and output a difference between the voltages; an output transistor receiving at its base an output voltage of the differential amplifier circuit and outputting from its emitter charging current; a capacitor charged with the charging current to hold the voltage at the output terminal; a bias element generating a voltage substantially equal to the given voltage of the level shift circuit; and a resistance element provided between the bias element and the output terminal for controlling discharging current of the capacitor.
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