BG770GL TE-A boards drwas 14mA idle current

IoT Modules
1

We are trying to test BG770GL TE-A board on LTE-EVB-KIT board, removing Resitor 104 and injecting the supply into the VBAT testpoint.
After sending AT+CFUN=0 we still measure 14mA current.
We think this current is probabling comming from the two CP2102N USB to serial chips that are supplied by the same supply as the BG770.
Is there a way to make the accurate measurements to see the uA residual current of the device without the 14mA or to remove power for these two componentss?

2

Hi Dmawas,

Please find attachment for consumption test manual :slight_smile:
BG770A-GL & BG950A-GL(Cat.M)_Power Consumption Test SOP_20220124.pdf (1.8 MB)

3

Thanks for your document,
the EVB board P/N I have bought recently is Q1-A0770 and not A0808.

Do I need to get this newer version ?

I was using a document got from your support team showing to remove R104. I have done this (but did not remove the tantalum cap).
It seems that with BG770 TEA, the USB to SERIAL chipset are powered by the 3V3 drawing about 14mA.
Anyway to suppress this current with my current EVB ?

BG96&BG95 power Consumption Testing Method tip.pdf (234.8 KB)

4

So Sorry for the late response.
Could you please share a image for the Q1-A0770 ? i think it ok but better double check it.

> It seems that with BG770 TEA, the USB to SERIAL chipset are powered by the 3V3 drawing about 14mA.
Yes, you can use Power supply to power EVB.

5

image
image1024×768 281 KB

Attached the EVB board used.
Can you reply on the usb to serial chipsets drawing 14 mA ?
Thks

6

Actually,
AT+CFUN=0 just only disabled RF, you need set AT+QSCLK=2 and then pull DTR pin to High, PON_TRIG to GNS stage…

7

Thank you it seems we were not putting PON_TRIG to GND.
But now we are measuring a minimum of 750uA with BG951 TEA.
We read that this could be the Automatic Power On circuit that draws about 700uA.
Can it be disabled to see the real power consumption ?

8

With BG770 TEA, we measure in PSM mode bottom line current to 95uA when disconnecting the Auto Power switch on the TEA board.In documentation we should be at 1.4uA when USB uart discativated. We are not using USB but main UART to communicate.

When we disconnect the UART_DBG of the TEA, the low current goes down to 30uA.
When this UART_DBG usb is disconnected, we cannot use the MAIN UART to communicate even when putting PON_TRIG high.
Do you have any explanation of above high current measurements and UART_DBG influence ?

9

Hello,
for μA level current consumption, we suggest to use Q1A0808 consumption EVB borad to test.
so 95μA should be caused by current leakage, because of you are using Q1A0770, we are not suggest test consumption with this borad, and DBG_UART connect will not influenct consumption actually.
for DBG_UART, if it not inderted usb cabel, the PON_TRIG will not take effect and it will be keep low, so we cannot communicate, the usb cabel just like supply to PON_TRIG.

10

Ok thanks for your help.
So we need to keep a powered USB cable connected to the DBG_UART to have the PON_TRIG system powered.

I will check if I can get the new EVB boardQ1A0808.

Thanks again for your support…