major power issues

I’m using
hw 2.6
sys v1.31
app v2.30

First Issue:
I was using my DSO Quad while it is plugged into USB
The charge light was red, when it changed to green, the unit appeared to turn off, the power switch is still in the ON position
I can wake it up by pressing any button, there is no splash screen

This happened at night when it finished charging, but I thought it was off so I never turned off the power switch. This caused the battery to become completely drained next morning. (I turned off my computer so no power came from USB afterwards)

Second Issue:
Also after one such charge cycle (charge light was green), I rebooted the device and the battery indicator only showed half full (Vbt was +3.81V). However now the red LED is brighter than before, weird. Rebooting the device again showed battery at 80% and Vbt = +3.97, I don’t know why but it doesn’t seem to update charge levels. The USB cable is plugged in during this time. If it reaches near full charge but I unplug the cable, it drops to about 50% again.

I doubt the green light means finished charging. From what I’ve seen it indicates screen saving mode when the device is on but screen is off (generator for example still works). I never tried to charge it to 100% (it’s actually better for the battery life) but I think the red indicates when it’s charging, so no red means no charging (or finished).

Looking at schematics it confirms that red is CHRG and green is /SLEEP.

I too am a little confused by the LED indicators. They show a single part with 4 leads on the schematic (D10A & D10B). As you have pointed out, the pins 1-4 cause the red charge indication. The pins 2-3 cause the green sleep indication. For some reason, the pins 2-3 location on the schematic indicates yellow+green. Does red +green = yellow? If so, would the yellow indication represent charging while in sleep mode? I can not find any 4 lead two color LEDs. If pins 2-3 were a 2-color LED, then reverse polarity can never be achieved with it’s present connections unless I am overlooking something in the schematic. The /SLEEP circuit is connected to STM-I/O pin and the STM is powered by the 2V8, so the STM could never reverse bias the pins 2-3 LED for Yellow.

Any clarification of this matter would be helpful.

I think that’s error and should be marked only as green. It does indeed happen when you charge it and it goes to sleep, both LEDs light so it looks orange/yellow.

the green light means if the Quad is in power saving mode (600s with no button pressed, Quad will get in this power saving mode), if you see it is light , just means it is in power saving mode
while the red light means if the battery in in charging .if it is red, it meaning the battery is in charging via USB, if not red , it means the battery not in charging, there is lots of cause for it is not in charging , maybe the USB is not connected , maybe the battery in full. notice when Quad in power up, the battery will not be charged , because the PC can only supply a current no more than 500mA, if the Quad is powered up , the LTC4054 can not charge the battry, so, even your battery is not full, it can not be charged(the red light is off)

can somebody clarify the difference between bright red and dim red on the LED?

having a red/green bi-colour LED for indicate charging and sleeping just doesn’t make sense at first glance, especially since nothing ever mentioned sleep-mode even existing

does anybody have expected battery life estimates for the sleep mode? if it can’t last several days, then I think I’d rather eliminate sleep mode

Thank you HugeMan, this post was very helpful and appreciated by all. This info and the back-light power save timer need to be flagged for addition to the User Manual.

So there you have it folks, when the DSO Quad is turned off, then the battery can charge with the USB cable. This would explain some people’s observations. It also makes sense that the “DSO Nano V2” will charge while turned on because it uses less current and has a smaller battery. The “DSO Nano V2” has a 3.3K program resistor, where the DSO Quad has a 2k program resistor. The LTC4054 specs sheets states:

“In all modes, the voltage on this pin-5 can be used to measure the charge current using the following formula:
IBAT = (VPROG/RPROG) • 1000”. So if you observe 1.0V on DSO Quad LTC4054 pin-5 then the battery charge rate is 0.5ma x 1000 = 500ma. For the DSO Nano, the same voltage would indicate 333ma battery charge rate.

So use this formula if you want to determine the actual charging current for your battery. The spec also states that if the Vprog (pin-5) exceeds 1.21V then the battery charging is terminated.