Part Number: LM3658SDEV
We use part LM3658SDEV as our battery charger. We ran into a problem as follows.
steps
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1. power on device
2. plug in battery. stat1/stat2 show battery is charging (passes test)
3. wait few hours
4. stat1/stat2 show battery is fully charged (passes test)
5. unplug line power and we detect line power lost and battery power active. battery takes over (passes test)
6. do not plug in power. wait until the battery completely dies. (passes test)
7. reconnect line power expect that the battery will start to charge again. however, we find that stat1 and stat2 are BOTH OFF [Power-Down, charging is suspended or interrupted] (test fail) and remain in this state.
It seems that when we drain the battery completely, we are unable to get it start to charge again. CHG_IN (pin1) is a 5V so it should exceed the BAT vol of 3.7 PLUS the small threshold required to start the charge.
The ONLY way we can fix this so far is to UNPLUG the battery AND unplug line power. Then plug both in and then the battery starts to charge. I cant ask my clients to unplug the battery.
If we do NOT allow the battery to fully die and just reconnect line power after 15 minutes, it charges back up just fine. The docs specify a case of EN_b low might cause this but i am at a loss what to do.
Pls assist on how to fix this problem. We cannot ask clients to unplug a battery in this scenario.
thanks
/Z
DIAGRAM
https://www.dropbox.com/s/y4bu077himj49vo/battery.png?dl=0
BATTERY
DESCRIPTION
Battery is 3.7v li-ion polymer battery 357090 battery 3000mAh Li-Polymer Battery
BATTERY specifics
Brand Name:Longyun
Set Type:Batteries Only
Model Number:3.7V Polymer Battery 357090 3000mAh
Type:Li-Ion
Nominal Capacity:3000mAh
Size:3.7V
Product Description
Features:
Product name: For Tablet PC/ CUBE U25GT /3.7V lithium polymer battery 357090 cable/for Ericsson S18 original Road N70
Product volume: 3000mAh
Product size:3.5*70*90mm
Product voltage:3.7V(nominal) & 4.2V(full voltage)
Product description:
Battery Lead: white, red and black line, the line length of about 3-5CM;
Inside with protective board parameters: charging cut-off voltage of 4.25V, discharge cut-off voltage of 2.75V, allows the maximum current 0.5A, with overcharge, over discharge, short circuit protection board.
Product characterist:
High discharge platform, the average voltage exceeds 3.7V, low resistance, fast charge time
Good security, with over charge protection, over-discharge protection, overcurrent protection
The protection IC technical parameters: Overcharge protection voltage 4.20V ± 0.05V
Over-discharge protection voltage 2.7V ± 0.1V
Over-current protection 3.0 ± 1.0A (2.7V ~ 4.25V)
The discharge temperature: -20 ° C ~ + 60 ° C
The protection IC parameters: Overcharge protection voltage 4.20V ± 0.05V, over-discharge protection voltage 2.7V ± 0.1V
High voltage, high energy density
Long cycle life, high safety
Shape, size, then the Spirit
Self-discharge, pollution
Application: MP3 / MP4, Bluetooth / GPRS / GPS mobile phone, PDA, small toys, digital cameras and video camera and other digital products.
Product future:
A variety of dimensions: type and capacity, available, applicability;
Quality assurance: A product used batteries, high capacity, low internal resistance;
Stable performance : long life cycle: continuous charge and discharge 1000 times, the battery capacity of not less than 80% of the rated capacity;
No memory effect : at any time to charge and discharge;
Safety: Built-in Seiko circuit protection board has no fire at short circuit, overchage, over discharge, shock , vibration, acupuncture, heat, and other state, no explosion and so on.