Hello,
I'm trying to build o rock solid battery bank and usb charger.
I'm NOT trying to develop anything with ready IC for control.
I have the basic step up concept on Multisim 12. Circuit Attached.
I have all the knowledge base about usb pinout. I can charge apple and android devices with the proper signals on D+ D-.
I have simulate the circuit on the charging side. Works ok with current limiting on 0,7A and voltage Limit on 4,2V. I think is proper handling of li-po cell.
I didn't dimension correctly the power circuit at all. for example i know that 2n2222 is not ok... so as other parts on the power circuit.
I read that 741 can do square generation and another 741 can integrate that to make a triangle wave. So for now i just put a triangular source.
For feedback and pulse on transistor another 741 used as comparator. Compare the triangular and the reference voltage (i don't know how to create this, maybe is feedback from output) and then we have the PWM signal that goes to transistor gate. Capacitor in series used to remove DC offset.
Please help on:
1.the power section dimensioning
2.comment on charging method (from usb)
3. comment on triangle generation using 2 741
4. comment on PWM generation using 741 as a comparator.
5. the feedback generation for regulation on 5V.
Thanks all.
I'm trying to build o rock solid battery bank and usb charger.
I'm NOT trying to develop anything with ready IC for control.
I have the basic step up concept on Multisim 12. Circuit Attached.
I have all the knowledge base about usb pinout. I can charge apple and android devices with the proper signals on D+ D-.
I have simulate the circuit on the charging side. Works ok with current limiting on 0,7A and voltage Limit on 4,2V. I think is proper handling of li-po cell.
I didn't dimension correctly the power circuit at all. for example i know that 2n2222 is not ok... so as other parts on the power circuit.
I read that 741 can do square generation and another 741 can integrate that to make a triangle wave. So for now i just put a triangular source.
For feedback and pulse on transistor another 741 used as comparator. Compare the triangular and the reference voltage (i don't know how to create this, maybe is feedback from output) and then we have the PWM signal that goes to transistor gate. Capacitor in series used to remove DC offset.
Please help on:
1.the power section dimensioning
2.comment on charging method (from usb)
3. comment on triangle generation using 2 741
4. comment on PWM generation using 741 as a comparator.
5. the feedback generation for regulation on 5V.
Thanks all.
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