Hi.I have decided to design a custom charger for my devices.I am going through the electrical analysis for the time being.So I needed some help with that.

Suppose you had a sine wave coming from your outlet.Suppose you had a diode in series with that AC source.During the half-cycle that the diode conducts ideally there is no voltage drop on the diode and Vin=Vout.During the half-cycle that the diode doesnt conduct the voltage drop on the diode is Vin and Vout=0.Now supposed you added a inductor in series.We again split the cycle into 2 half-cycles when during one diode conducts ,while during other diode doesnt conduct.Because you have cycle after cycle by taking into consideration the equation of the inductor:
dI/dt = V/L you can say that dI/dt = dI_{halfcycle}/T_{halfcycle} = V/L or that dI_{halfcycle} = 2V/Lf_{outlet} (in Europe it is 50Hz).

Suppose you added a resistor in series to all of these components.The resistor draws a average current I=V/R.So if you want to have a continuous mode V/R>2V/Lf or Lf>2R.Am I correct?

 

A schematic would be nice.
I have seen supplies using a large inductor. The problem is the LARGE INDUCTOR. With 50hz the inductor needs to be larger than with 60hz.
Another problem is your supply sits on the power line and has no isolation.

 

 

I used 250Vac 50hz. Vout is about 110Vdc. I had to add D2 to make it work.

 

I used 250Vac 50hz. Vout is about 110Vdc. I had to add D2 to make it work.
View attachment 365242

Yes you are correct, I forgot the flyback diode so the return path of current isnt through the battery when diode is off.

 

What voltage, current do you want for an output?

 

Using a bridge rectifier would cut your inductor and filter sizes in at least half.

 

If you have continuous current, then the output voltage must be the average of the input voltage, which is Vpeak/π, or if you use a bridge as @crutschow suggests, Vpeak*2/π. How are you going to utilise 103V (or 206V)?

 

If you have continuous current, then the output voltage must be the average of the input voltage, which is Vpeak/π, or if you use a bridge as @crutschow suggests, Vpeak*2/π. How are you going to utilise 103V (or 206V)?

Ah yes I missed that too.

 

Most often, when developing a circuit for any type of power supply, including a battery charger type, there is a specification for voltage, and usually a current.
R.S. asked that in post #6! I ask for it again in post #10!
So far I have seen a few partial circuits without much hint towards the required design output. Rather strange.

 

Most often, when developing a circuit for any type of power supply, including a battery charger type, there is a specification for voltage, and usually a current.
R.S. asked that in post #6! I ask for it again in post #10!
So far I have seen a few partial circuits without much hint towards the required design output. Rather strange.

I am looking for the circuit of the battery charger I can always use a capacitive voltage divider with low input impedance before feeding it to the rectifier.

 

An easy scheme will be the half wave plus flyback diode scheme charging a 96 volt battery pack, whic might actually be a 96 volt string of 12 volt batteries. 110 volts DC would charge it at a reasonable rate. But the really simple scheme will be a transformer designed to provide whatever voltage is desired. The transformer will also provide adequate isolation, unless an autotransformer scheme is used. In my stack I found a stepdown transformer 120 volts to 100 volts, for operating a sound system intended for a country with 100 volt service. But not isolated! That could be OK for charging a battery sitting on a shelf, but rather hazardous for charging a car battery in place in the car.

 

An easy scheme will be the half wave plus flyback diode scheme charging a 96 volt battery pack, whic might actually be a 96 volt string of 12 volt batteries. 110 volts DC would charge it at a reasonable rate. But the really simple scheme will be a transformer designed to provide whatever voltage is desired. The transformer will also provide adequate isolation, unless an autotransformer scheme is used. In my stack I found a stepdown transformer 120 volts to 100 volts, for operating a sound system intended for a country with 100 volt service. But not isolated! That could be OK for charging a battery sitting on a shelf, but rather hazardous for charging a car battery in place in the car.

Ok thanks.

 

Westill have not been told about what the battery voltage is.
Without knowing the voltage or the current it is rather difficult to design an efficient charging circuit. MZ Groves, being a computer engineer, certainly should be able to inform us as to the battery voltage. That really is quite important for a battery charger.

 

Westill have not been told about what the battery voltage is.
Without knowing the voltage or the current it is rather difficult to design an efficient charging circuit. MZ Groves, being a computer engineer, certainly should be able to inform us as to the battery voltage. That really is quite important for a battery charger.

Well yes sorry for keeping you w8ing.I messed up.Well I want to charge my phone so its 5V ,1A.

 

Westill have not been told about what the battery voltage is.
Without knowing the voltage or the current it is rather difficult to design an efficient charging circuit. MZ Groves, being a computer engineer, certainly should be able to inform us as to the battery voltage. That really is quite important for a battery charger.

Right

 

Well I want to charge my phone so its 5V ,1A

That's a bog-standard USB 5V supply. Cheaper to buy than to build. The charge control circuitry is inside the phone.

 

Your proposed circuit has nothing that will drop the voltage to 5V. How are you expecting that to work?

 

Your proposed circuit has nothing that will drop the voltage to 5V. How are you expecting that to work?

Well im looking for the circuit of the rectifier.I can always use a inductive or capacitive voltage divider(to not waste heat) to reduce the voltage to appropriate levels.

 

Well im looking for the circuit of the rectifier.I can always use a inductive or capacitive voltage divider(to not waste heat) to reduce the voltage to appropriate levels.

You can, but then you would need isolation, so you would still need an isolating transformer.