| 摘要 |
Saturation connection is performed between the gate and source of a depletion-type n-channel MOS transistor, and the depletion-type n-channel MOS transistor generates a first constant current. A current-mirror circuit is connected to the depletion-type n-channel MOS transistor, and mirrors the first constant current. A first enhancement-type n-channel MOS transistor generates a first constant voltage which depends on the first constant current, when receiving the first constant current mirrored by the current-mirror circuit and being activated. A first resistance element is connected between the first enhancement-type n-channel MOS transistor and ground. A second enhancement-type n-channel MOS transistor is connected to the first enhancement-type n-channel MOS transistor and the first resistance element, and controls generation of a second constant current in the first resistance element in accordance with activation of the first enhancement-type n-channel MOS transistor. A second resistance element is connected between a power-supply line and the second enhancement-type n-channel MOS transistor, and generates a second constant voltage which depends on the second constant current.
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