Help me with designing PLL charge pump

[niyut]

PLL_charge_pump design

hi, all

I am doing my project on PLL charge pump design. I chose single ended
chare pump design with active amplifier because it is very common.

I am not able to find research paper on this design.

Also, in my project.
one specification is "Charge pump current should be controllable by
3 precision bits. "

I do not able to get idea how i can implement this kind of architecture in my design
because this is my first analog project.

If you guys any papers related this project can you plz.. send me or any book name. it will be very helpful for me.

Thank you,
niyut

 

[lyrix]

Re: PLL_charge_pump design

you can control the current mirror, enalbe/disable part of your current mirror by forcing gate voltage to VDD or GND

 

[paladinzlp]

Re: PLL_charge_pump design

You can use inverse-linear current mirror as charge pump

 

[mady79]

Re: PLL_charge_pump design

I think 3 bits are basically used for precision .so you have to source /sink the current based on this 3 bits used for correction in charge pump voltage .
Simple way is to based on the precision source/sink current needed you can mimic your charge pump circuitry carrying small precion current .you can have a resistor based 3 bit D/A converter and feed the analog as an input to the precision circuit .


Let me know the final approach which you are using .

 

[fashion]

PLL_charge_pump design

I think you can use current control to change the charge pump current ,than you can get 3 bit control on it !