Power supply for a system

[andre]

Hi guys,

I have a device with 4 subsystems that needs to be powered up from rechargeable batteries, the batteries needs to be charged up through a solar panel. I need + and - 9V for an opamp, 5V for the microprocessor, 3.8V for a transmisson unit and 1.2 V for the opamp input. All the volatges are DC. I need help with the batteries charger circuit and how to power up the system components using the chargeable batteries when they are full charged. Now I am thinking I need three 9V-rechargeable batteries, and use few LM 317T regulators to power up the system. I also have a 16 V solar panel with 15 ma current. but just not sure if this will solve the problem. Please, any feedback is welcome and appreciated.

Cheers!!

 

[(*steve*)]

What current do you require from these supply rails?

The LM317's could easily use up the entire 15mA your panel produces.

 

[andre]

right now I have a solar panels able to provide 200 mA. I need to power up the opam with just 2 mA, but I need + and -Voltage, do you know of an opamp that takes only a positive volatge supply and still produce a symmetric circuit. I am using the opamp to make a Howland current pump and for that circuit to do its job, it needs to opamp power supply should be symmetric?

 

[(*steve*)]

Perhaps you can post the circuit diagrams you have.

Are you just trying to create a current source?

Perhaps you should give us to overall picture of what you're trying to achieve.