| 摘要 |
An output unit includes a constant current source, a switching transistor that dumps the constant current when a first signal is low, and a switching transistor that outputs the constant current when a second signal is low. A drive unit includes an inverter that generates the first signal responsive to a digital signal, and an inverter that generates the second signal responsive to the digital signal inverted. Power supply terminals of the inverters are connected to an output of the current source, and the high-level voltage of the digital signal is higher than the high-level voltage at the power supply terminals. Accordingly, operation timing of the inverters is slower when changing from high level to low level, than when changing from low level to high level, so that the switching transistors do not both turn off simultaneously. This suppresses current fluctuations of the current source.
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