Hello,
I have built chargers with the L6924D and they do what they should, charging and detection and error-reporting works.
The charger is not permanently connected to the battery but has a 3 pin spring loaded connector. Sometimes there is a connection missing because of dirty contacts or something similar and it does not charge. If GND an NTC are connected, it will report an Error because no Charge current flows. if GND and Bat+ are connected, it will report because of temperature out of range. The only problem I have is when Bat+ and NTC are connected, but GND is missing. The L6924D will output PWM Signals with around 1kHz and a ratio of 90% für Status1 and 10% for Status2.
Any idea what could be the Problem?
Attached you can find the schematic. Additional info to the schematic:
-bottom left is a discrete transistor logic, which just makes three LEDs out of the two status-outputs. blue when Status1, green when Status2, red when Status1&2, all off when no battery connected. I disconnected the logic and just used pullups on the status pins, but it did not solve the problem.
-The NTC connection is used to detect an attached charger on the battery side.The NTC of the battery is not connected directly to Vref, but is amplified by 2.5x, then goes to the battery, then it is divided by 2.5x and goes to the TH pin of the L6924D. That works fine. I tried to remove the two Opamps and directly conect the NTC to the L6924D as in the datasheet, but it did not solve the Problem.
