I'm designing a capacitor discharging control circuit. Its principle is as follows:

• Voltage monitor 1 :
  • upper limit, Output low level when voltage higher than 14.39v

• Voltage monitor 2 :
  • lower limit, Output low level between 11.62v-10.12v

The monitor will output low to pmos to turn it on, then the latching circuit will hold it to discharge.
Result:

• Load is connected between 11.64v – 14.30v

My question is:

1. I want to change the current source to 100mA and R2 to 150Ω(which can ensure the output current is 15V), but the output can not be controlled after that change.
2. The Load is must around 10kΩ， I cannot change it to other values(otherwise it will not work.)
3. Is there any other ways to control the discharge? I would like a circuit as a reference.

Thanks in advance!

 

It's not clear at all what the reason is for this circuit or what it's supposed to do.

What's the purpose of controlling the capacitor discharge?

 

And why all the complexity ?

 

Not to mention the fact that the 3K resistor is already discharging the cap faster than your 10K “load”, which, by the way cannot pass anywhere near 100mA at 15V.

 

Looks like another solution in search of a problem. Anything to make a buck in the "EE business".

“If you can't dazzle them with brilliance, baffle them with bullshit.”

-- W.C. fields

 

It's not clear at all what the reason is for this circuit or what it's supposed to do.

What's the purpose of controlling the capacitor discharge?

Thanks for the reply! This circuit is a part of an RF energy harvesting system Because the energy source is limited so I need a capacitor to store the energy until it reaches the upper voltage limit, then discharges. Now I realize the R2 cost too much energy, I think I need another way to realise my circuit. Is there any ideas? Should I use an IC to achieve it?

 

Not to mention the fact that the 3K resistor is already discharging the cap faster than your 10K “load”, which, by the way cannot pass anywhere near 100mA at 15V.

good reminder, I need to try to solve it

 

I don't think there is anything to solve. IMHO, there is literally nothing you can do that will allow you to create much more than a curious toy. It will have no useful application. However, be my guest on this Sisyphean task.

 

All You need is a single Zener-Diode connected across the Capacitor(s), and that's it.

Choose a Voltage lower than the rated Voltage of the Capacitor(s).

The same effect could be achieved by putting multiple
standard Diodes in series to achieve the desired Voltage, instead of using a single Zener.
.
.
.