Greatings to the TI e2e team,
I'm currently working on a college project that consists in a solar powered NiCd/NiMH AA 1,2 V single battery charger, we're using the schematic shown in the BQ2000's application note, but without the resistive voltage divider ( R6,R7 and R9), we use only a 100 kohm resistor (R1 in the datasheet) between bat+ and the bat pin of the integrated circuit (pin 4) as well as a 0.1 uF polyester film capacitor connected to Vss. The rest of the circuit remains as in the datasheet. The battery is charged at a constant current of about 300-400 mA, the DC+ voltage is supplied by the boost converter connected to the solar panel and have about 7 V, but if the battery is removed the LED starts blinking instead of turning off and the bat+ voltage oscillates between 6 and 0.9 V. We've replaced the boost converter with a bench power supply, but the result is the same, if the battery is removed the LED starts blinking, and oscillations are present at Vbat+.
What is causing such problems?
Best regards,
Daniel Almeida