Hello, I'm having trouble making my 2x charge pump architecture switch to 1.5x. I have attached pictures of my schematic. The idea is in order to switch the 2x architecture to 1.5x is to connect a capacitor between nodes A and B to limit the output voltage. The switching is controlled by a mosfet which is in series with the limiting capacitor. In order to control the mos switch, the vbias node, which has a value of either 1.5 and 0, is fed to the gate of the mos switch. So the goal is to turn on the mos when vbias is 1.5 and off when vbias is 0. The problem at hand is that the mos switch is difficult to saturate because drain and source voltages are nearly identical. Are there any possible solutions?
Attachments:
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forums-1.5x.png
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forums-4.png
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forums-3.png
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forums-2x.png
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