Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Capacitive Boost or Charge-Pump DC-DC Converter

Status
Not open for further replies.

WASDQWERTY

Newbie level 4
Joined
Oct 23, 2019
Messages
6
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
49
hello, i would require some advice on the capacitive DC-DC Converter that can generate several selectable DC voltage sources from a single given DC voltage source. The generated DC output voltages are multiple times of the input DC level when unloaded. It uses the concept of the Dickson charge pump, by multiple flipping of the charged capacitor onto another capacitor. The power transistors, controller and the capacitors are meant to be integrated together. The output should be able to efficiently deliver acceptable amount of power in tens to hundreds of mW.

I am using 0.18um Cmos technology simulated in Cadence-virtuoso and would like to seek some advice because i'm new to the IC-design industry. I hope to seek your understanding to guide me through this project.
 

Diagrams of the Dickson frequently have two clocks driving it. These are in fact a full H-bridge which turns the DC supply into AC applied to the network. The circuit becomes similar to a half-wave parallel multiplier.

Each capacitor charges to a greater level than the one before it.

Dickson V multip half-bri 6 caps 6 diodes 3_6V supply.png

You don't necessarily need to assemble 6 stages. It depends on what range of voltage outputs you wish.

Your specs ask for hundreds of mW. This requires sufficient Amperes going through all components need to be robust enough to handle Ampere levels.
 

Thank you for your advise. the project specs is asking for hundreds of mW and producing at least 3V voltage output as it is for portable electronics. I also cannot use diodes in my circuit, i have to use mosfets
 

3V voltage output as it is for portable electronics. I also cannot use diodes in my circuit, i have to use mosfets

Then do you have a schematic to start from, which uses mosfets?

What is your power source? This creates a challenge for your project, because if you want 3V @ 400mW output, it requires a draw approaching 1 Amp from a 1.5V cell.
 

i have to use an IC-design software which is Cadence virtuoso to simulate the circuit that i designed. Within the software i can place a DC source.

I'll have to design the circuit from scratch using past references or research that is why i do not have a schematic.
image.JPG

so far i've been reading up on this topology whereby i have to change the switches to mosfets

- - - Updated - - -

in this case, how do i determine which W/L to use for my mosfet
 

Then do you have a schematic to start from, which uses mosfets?

What is your power source? This creates a challenge for your project, because if you want 3V @ 400mW output, it requires a draw approaching 1 Amp from a 1.5V cell.

image.JPG
I've been reading up on this topologic where they advised my to reconfigure the switches into nmos or pmos. apart from this i will also have to design my own clk and clk bar signal.

As i am still currently learning as a student, i hope you can understand that I do not know how to express my concerns properly due to the lack of knowledge. Thank you
 

It's hard to be certain exactly who originated this charge pump topology (whether Dickson or Nakagome). To make some progress in this discussion here is my basic simulation showing how to connect transistors to the flying capacitor.

Nakagome V doubler 1 cap 1V supply 1 clk load gets 1_7V.png

This illustrates the concept.
You need to add stages in order to attain 3V.
You need to maximize efficiency if you want a few hundred mA.
You need to design an oscillator that produces sufficient voltage to drive all charge pump stages.
 

sorry, can i ask, in this case when I characterize my mosfet, what will my W/L be?
 

While I'm inexperienced at IC fabrication, it's obvious there are hurdles because your transistors need to turn on with a small supply voltage.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top