aaron_do wrote on Nov 19th, 2013, 10:18pm:Hi,
you can use a -ve charge pump. It requires a ring oscillator an the charge pump itself. Why do you need a minimum number of components? You're in the wrong design age if you're worried about complexity. Problem is it needs to be on as long as you want to enable/disable, so power consumption is an issue.
I still don't get why you're so keen on using PMOS...
Aaron
I am not worried about circuit complexity. I am worried about power consumption. Since it is a passive tag and it harvests energy, whatever power I harvest, some of the harvested energy is utilized for Chargepump and other devices.
Even I am not keen about PMOS. As u said, it is PMOS or NMOS, I need voltage source. The only Q is who wil provide the voltage.
During energy harvesting, Rf input signal is in the order of few mV and the control voltage for NMOS SPDT switch is more than the peak of the RF input.
I am thinking of using a start-up circuit to generate required voltage for SPDT switch. Once I get some voltage, then I can enable/disable the switching scheme.
Pls correct me if I am wrong.