MC34063 mp3 player charger - Battery charger circuits

This mp3 player charger electronic project circuit diagram is designed using the MC34063 circuit which is a monolithic control circuit delivering the main functions for DC DC voltage converting.

The output voltage of this MC34063 mp3 player charger will deliver a 5 volts output voltage at 660mA output current .
The MC34063 mp3 player charger contains an internal temperature compensated reference, comparator, duty cycle controlled oscillator with an active current limit circuit, driver and high current output switch.
The output voltage is adjustable through two external resistors with a 2 % reference accuracy.
This IPOD , MP3 device charger circuit require an input voltage from 9 to 15 volts DC .
Modify the VR1 variable resistor you can adjust the output voltage at 5 volts .
The L1 coil has 75 turns of 0.5 mm enameled copper wire on a Neosid powdered iron core 17-732-22 .

Recharge a 9V NiMh battery with a Solar Panel / Constant Current Generator LM317LZ

 
If you enjoyed the previous post solar-powered Arduino board, you should keep reading this one as well to improve your solar power generator. In fact, with that setup the 9V battery would decay too soon: A NiMh (Nichel – metal hydroxide) battery must be recharged with a constant current generator, a solar panel alone is not.

In order to do so, we can assemble a quite simple circuit using the following components:

    LM317M or LM317LZ
    A 200Ohm trimmer
    10Ohm resistance
    A LED to check if the current is actually flowing

The core of this circuit is the integrated three-terminal adjustable linear voltage regulator LM317. The ‘adj’ pin is a control terminal that is used to adjust the output current. So, the trick is to use a variable resistor (in our case, a trimmer with a small resistance put in front of it) to set the current at a definite value.

With an input DC voltage of max 24V, and the resistances shown in the diagram, one can obtain an output current of:

I_out = 1.2/(10 + R_trim) [A]

This current must be less than 1/10 of the battery output, e.g. for a 750mAh battery the output current must be less than 75mA. As usual, it is customary to insert a capacitor (100uF should be ok) in parallel at the input node to smooth out fast-varying voltages.

Make a DIY LM317 Power Supply

     HI. Being able to poke voltages into your projects will help you debug. You can buy an adjustable power supply for $50 or so, or build your own from a kit (another one) Just look for any power supply kit that has a LM317 in it.

    You can also build it for $10 using a 9V battery as input and test clips for outputs. This won’t be able to provide a lot of power (cause its just a 9V) but it can go pretty far for testing and debugging.