| 摘要 |
A tub structure underlying a first well in a semiconductor integrated circuit is charge pumped to increase electron collection efficiency in the tub structure. A charge pumping circuit applies the biasing voltage via a second well. The current in the tub structure is monitored to determine when to pump charge into the tub structure. The pumping biases the n-tub to voltages as high as twice the supply voltage magnitude, (2Vcc). The tub current is compared to a minimum current threshold and a maximum current threshold. The charge pump is disabled when the tub current exceeds the maximum threshold and is turned on before the tub current goes below the minimum threshold. The maximum threshold is for keeping the tub structure from exhibiting an undesirable standby current. The minimum threshold is to keep the tub structure biased enough to achieve a desired electron collection efficiency.
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