Charger for lead acid battery.

[Thommyy]

I need to make a charger for lead acid battery which will be controlled by MCU. The batteries are connected in series of 6pcs, that means 72V
This is a UPS backup power supply.
Can you recommend me some power supply where the output voltage and current could be controlled externally, for example PWM or via some communication.
The input voltage is max: 95V
Current max: 3A

I know that Analog Devices has different circuits of ready chargers but I haven't discovered any that would be close to my parameters.

Thank you for your answers and help.

[mtwieg]

A few options:
1. Do everything, including voltage sensing, current sensing, and PWM generation with the MCU. The charging algorithm implemented entirely in firmware. The firmware will also be responsible for the high speed voltage and current control loops, requiring a much greater firmware effort.
2. Use a generic PWM controller IC (preferably one which has average current-mode control). The MCU doesn't have to manage the high speed voltage and current control loops, but can adjust their setpoints in order to allow it to implement the charging algorithm.
3. Find a more specialized PWM controller IC which does some/all of the charging algorithm.

One part maybe worth looking at is the UC2909. It's a simple pwm controller but it also can implement a simple three-stage charging algorithm. It will need some external circuitry to interface it to the high voltage power path. I'm not aware of any suitable PbA charger ICs rated for such high voltages (LTC4013 is the closest I'm aware of at 60V).

Hard to give more specific guidance without knowing about your background (power electronics and MCU coding). If you're new to power electronics I would strongly recommend starting off at 12V and then scaling up only after mastering that.