The Dickson Charge Pump is a DC-DC converter that produces a higher voltage than the supply voltage. Unlike the boost switching DC-DC converters which require large inductors, the Dickson Charge pump is designed using MOSFETs as switches, and they utilize energy-transfer capacitors instead of inductors, therefore the size, non-linearity, and interference issues related to the usage of inductors in ICs are being eliminated. This circuit is widely implemented in various IC applications especially in non-volatile memories like the Flash and EEPROM. That being said, there is yet another interesting application of the Dickson Charge Pump and that is - Dickson Charge Pumps being used in Phase-Locked Loops. Charge Pump based Phase-Locked Loops (PLL) are widely used as a clock generator in a variety of applications including microprocessors, wireless receivers, and disk drive electronics. The charge pump circuit is the heart of PLL. The chare pump (CP) based PLL is the most popular architecture. The CP-PLL derives its name from the fact that the phase detector (PD) output is a current source as opposed to a voltage source and "pumps" current into and out of the loop filter.
I found the working of a PLL to be interesting, so I had an idea of designing a Charge Pump for a PLL using open-source tools and Sky130PDK. After an extensive literature survey, I had decided to implement the design and layout of a Dickson Charge Pump, instead of a conventional Charge Pump. This is how I started to work on my design and I'd completed it till post-layout.
This project focuses on the design and layout of a Dickson Charge Pump in a 130nm technology node which is suitable for PLL applications. The device modeling was done using Sky130PDK from Google SkyWater.