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I want to build a lithium ion battery charger with tp4056 module but most of my power supply's voltage is 12-19 V

Datasheet says input voltage is 4.5-5.5v and current 1A

Can I connect 1-3 tp4056 module in series ?

I think it won't work because voltage drop not constant ( depends on how much module consume )

I thought to use l7805 or lm317 but 1A is seemed too much for them

Right now I'm thinking about using pwm circuit with MOSFET but If anyone have better idea , I want to hear it Also if I make pwm circuit to convert 19V (4A) to 5v , output current stays same or could it be 12A ?

Thanks for helping

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  • \$\begingroup\$ You must convert to an acceptable voltage range but why would you need 12A? \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Sep 10 at 0:42
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Can I connect 1-3 tp4056 module in series ?

No. They will not share the voltage equally. The one that draws the least current will get the most voltage, then it will blow up and probably become a short, putting all the voltage across the other one which will then also blow up. Don't do it!

I thought to use l7805 or lm317 but 1A is seemed too much for them

It's possible, but very wasteful. A 7805 on 12V has to dissipate (12V-5V)*1A = 7W, which would require a large heatsink to keep junction temperature below 125°C.

Right now I'm thinking about using pwm circuit with MOSFET

PWM alone is not enough. You need something to smooth the output and regulate the voltage. This is called a buck-mode switching regulator. Low cost switching regulator modules are readily available, and are much easier to use than trying to make your own.

Also if I make pwm circuit to convert 19V (4A) to 5v , output current stays same or could it be 12A ?

The power supply can be rated for any current above 1A, the load will only draw the current it needs. A switching regulator will draw even less current because it boosts current in the same proportion as it reduces voltage.

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  • \$\begingroup\$ I have another question about pwm circuit with MOSFET but I should ask another question for it . I can regulate voltage with l7805 (pwm output) Also About current question: For example load is 1 ohm and power supply's voltage is 12v (3A) so if I convert 12V to 5V , will current be 3A or 5A ? Power is same 12V 3A = 36W , 5A 5A = 25W \$\endgroup\$ – Mordecai Sep 10 at 1:39
  • \$\begingroup\$ With a switching regulator output power = input power - switching loss (eg.10%) so it would draw 25/12 = 2.08A +10% = 2.31A at 12V for 5A at 5V. \$\endgroup\$ – Bruce Abbott Sep 10 at 2:00
  • \$\begingroup\$ But power supply's max power is 36 W (change load to 2 ohm), So in 5/12 period = 12v / 2 = 6A (72W) and 7/12 period 0w average power 30W ? Also I think I can't make pwm circuit with N channel mosfet because load supposed to be between Vsupply to mosfet's drain and mosfet's source connected to ground but if I do that pwm doesn't work \$\endgroup\$ – Mordecai Sep 10 at 2:18
  • \$\begingroup\$ You can't use straight PWM on a TP4056. It needs a smooth continuous supply voltage, regulated to within 4.5~5.5V. A switching regulator smooths the current through an inductor and output voltage with a capacitor. Thus we consider the average (not peak) currents at input and output. \$\endgroup\$ – Bruce Abbott Sep 10 at 2:41

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