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DLPNIRSCANEVM: Battery supply

Part Number: DLPNIRSCANEVM

Hi,

I'm using the NIRSCAN Nano EVM module for a while right now. 

Since a few days I'm having issues with powering the device. 

I have a single cell 3.7V lithium ion battery connected. I have no thermistor connected since this battery is monitored with another safety device which also charges the battery. 

Sometimes I can not power the module anymore until I've plugged in the USB power supply. Until now I have no clue when this happens and what might cause this. 

After powering the module with the USB cable, the battery powering works fine again. 

It seems like there is some safety thing blocking the battery? Maybe because there is no thermistor connected?

Regards,

Nick 

  • Hello Nick,

    What is current rating of the battery? Did you try with another fresh/new battery?  It is very likely that battery is not able to supply power up current which may be higher than normal operation.

    The battery specification for DLPNIRScan EVM is Li-Polymer 3.7V 1700mAh (103450) Battery

    regards,

    Vivek

  • Hi,

    We have a 3.7V Li-Ion 2600 mAh battery which should be sufficient. 

    It can deliver up to 2.5A.

    I doubt it will be the battery specs because when I 'reset' the module with the USB supply it works fine on the battery again, included powering up.

    Regards,

    Nick

  • How are you using to interface to the EVM i.e. scan data collection?

    regards,

    Vivek

  • I'm using the expansion connector to communicate with the device. 

    I have the TX, RX and GND pin of this connector connected and power is over the battery connector.

    Regards,

    Nick 

  • Hello Nick,

    Is battery is also hooked to an external battery charger  while it is  connected to EVM? It is likely that system may getting into into a fault mode shutting off  power if it detects a signal unexpected on VBatt.

    regards,

    Vivek

  • Hi Vivek

    Yes, it is hooked up to a micro-controller which has a battery charger on board. The NIR module is not always powered for battery saving reasons.

    The micro-controller switches the NIR module on and off by use of a transistor (which can handle the current).

    Please find the lay-out below.

    If the charger is going into fault mode, can you please advice me on how to avoid this? 

    I guess I'll have to power the NIR in some other way, maybe on the USB + and -?

  • Hi Vivek,

    Do you have an idea when I can expect to get an answer? 

    Just that I can make my planning accordingly.

    Thanks in advance!

  • Hi Nick, 

    Having 2 battery chargers connected to the same battery is not recommended. You are suggested to use another power converter to convert the battery voltage to 5V and feed it through NIRScan Nano USB VBUS line. You can use the enable pin on this power converter to turn on and off the NIRScan Nano on demand from your MCU.

    Thanks & Regards,

    Hirak.

    If you feel we were able to resolve your query, kindly click "This resolved my query" on the resolving answer! 

  • Hi Vivek,

    Thanks for that information.

    I will try this and as soon as possible.

    Regards,

    Nick 

  • Hello Nick,

    Thank you. Let us know if your problem gets resolved.

    regards,

    Vivek

  • Vivek,

    I'm not able to feed the USB with 5V. Until now I do not find a suitable converter which fits the product. 

    All of them are relative big. Do you maybe have some suggestions? 

    Is there another option to power the device? Is is maybe possible to pass the charging safety circuit of change it? 

    Or power somewhere else on the device? 

    Regards,

    Nick 

  • Hi Nick, 

    Kindly try out these steps to help us understand the problem better:

    1. Kindly recheck the transistor polarity, because in the image you provided earlier it seems it is connected in opposite polarity (in reverse wrt the proper direction of current flow)

    2. Could you kindly check the input voltage at the J6 of NIRScan Nano when you are powering it through the battery? This will help us understand if the input voltage is too low after the Vec drop of the PNP BJT you are using.

    2. Also try attaching a 500uF-1mF large elctrolytic capacitor in parallel to the J6 line. This may help. 

    3. If it still does not work, kindly try connecting the battery directly to J6 (without hooking up your own MCU board), and try to turn on NIRscan nano and take a scan by pressing the scan button. Check if this test works without any problem. This will ensure that the unit is working properly. 

    4. Finally, if all of the above fails, the only options left are to power the device by feeding 5V to USB_VBUS or 4.5V to SYS_PWR line (using pads of C65/66/67)

    Thanks & Regards,

    Hirak.