Power bank battery charger is not Working!!!

Hi,

I have a Battery charger circuit of Lenovo power bank which uses the chip ACT2802 Active power manangement IC.
The datasheet link is shown below,,
https://active-semi.com/wp-content/uploads/ACT2802_Datasheet.pdf

The evaluation guide link is shown below,
https://active-semi.com/wp-content/uploads/ACT2802_Application_Notes.pdf

I dont have the specific schematic or board design of the circuit. But from the visual perspective the with some multimeter probing, I understood that the schematic circuit is same as the schematic in the evaluation guide (Note sure about the values of components). The snubber circuit is not there in the circuit (R9,C7).




Please see my findings below

1. While connecting USB cable on micro USB for charging. It works usually by direct shorting Vin and Vout internally. It gives 5V at the Output USB connector. It also charges the battery
2. While for testing, a single battery is connected and Vin(from MicroUSB) is disconnected. At that point of time, it gives 5V at the output USB for a second and then goes to 0V. Means Vout pin of IC is 0V.
3. Means Boost is switching at the initial time and then slowly stops boosting.

Please see the video of SW pin DSO output
[video]https://drive.google.com/open?id=0B7RFrp4jwtRtaHBLZ195QmZuX3MzLUlrbmRsT0xub WxfSU4w[/video]

Image :-


The SW pin switches initially then return to Battery voltage and stays constant there..


1. I want to know whether the IC is damaged or not..
2. If it is not switching, Then can I suspect the Inductor?

I beleive if the inductor have being bad somehow, it wouldn't even started to switch.

Where do you get power from? Is that power source capable to deliver enough current?

Hi proto,

While taking power from USB or adapter through VIN pin, it works and gives 5V. Now I Im testing with a single 2600mAh battery through VBAT pin. Let me check with powering from a bench. Thanks for the info.