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Microduino-BM module is an integrated single-cell Li-ion battery charge management,
power detection and LED indication, the boost to 5V output, LDO to 3.3V output of discharge management module.
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Features
- Charge and discharge management, power detection, 5v boost, 3.3v LDO highly integrated;
- DIP switch gear charging and discharging, a key to open, hibernation module;
- Small, cheap, stack, open;
- Unified Microduino interface specification, and rich peripheral modules can be easily and flexibly with other eligible Microduino interface specification modules, sensors for quick connection and expansion;
- 2.54 pitch row female connector for easy integration into breadboard.
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Specifications
- First, let's look at the interface of the module:
- A key switch
- A two tranches DIP switch gear
- One pair of 2.54 battery interface ("+" then the battery positive, "-" then the battery negative)
- UPIN27 on the role of interface has 5V, 3V3, GND:
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Charging
- First access external 5V charging power supply, and then switch to "IN", the module into the charging state, then four LED lights do Surge charging indication (detailed display mode, please refer to HT4901 documentation), the maximum charging current to 500mA, charging is completed * after the first switch to OUT, and then unplug the external 5V charging power.
- Note:
- Always follow the charging process: make sure switch to OUT, plug in the battery, charging access external 5V power supply, the switch in the IN, start charging, charging is completed, the switch to OUT, unplug the external 5V Charge power.
- Recommended charging power supply: Voltage 5v, current 600ma above;
- Not add pressure drop impact elements (diodes) in the charging circuit, so as not to reach the charging voltage, thereby affecting the charging current.
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Discharge
- Make sure the switch is in the OUT, after access to the battery, in the standby mode, short press button switch (time> 50mS), the module that wakes up from standby mode; boost output started at this time, while open UPIN27 the GND circuit: Interface 5V 5V output voltage, maximum current of 500mA; while 3V3 interface output voltage of 3.3V, the maximum current 250mA.
- When the battery voltage under-voltage (3.3V) or enter limiting / boost output short circuit protection, enter standby mode.
- Note:
- Make sure the switch is in the OUT and then start boost output;
- please do not toggle switch in Battery-powered process.
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Power detection
- Make sure the switch is in the OUT, after access to the battery, press button switch on the built-in battery detection; and through the four LED indicator for battery indicator, battery indicator after 3 ~ 5S closed.
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Standby
- (Standby circuit is disconnected UPIN27 the GND and BM can be controlled within the overall power consumption of 30uA)
- Make sure the switch is in the OUT, if any action after accessing the battery, then the default is in standby mode.
- When you've turned on discharge mode by pressing the button switch (3s above) to enter standby mode.
- Intelligent Detection: No charge input, no discharge output (<10mA) within three minutes into standby mode.
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Documents
- Snapshot of Microduino-BM schematic
- Microduino-BM Eagle source file 【download】
- Microduino-BM main chips and devices
The main components
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Development
- Battery: single 3.7v lithium battery;
- Recommended battery module is connected with 2PIN DuPont;
- Recommended power supply options: voltage 5V, current 600ma above, such as: computer USB, 5V phone charger.
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Applications
When viewing the board with the battery connector and switches closest to you, with the component side up, the battery connector positive (+) pin is on the left and the ground (-) pin is on the right. The pushbutton switch is on the left and the mode switch (IN = Charge, lever to the left; OUT = Discharge, lever to the right) is on the right.
After connecting the battery you must momentarily push the pushbutton switch to start the converter. You can stop the converter/turn off the power by unplugging the battery or by pressing and holding the pushbutton for a few seconds. To use the battery to generate +5 VDC and +3.3 VDC, set the mode switch (to the right of the battery connector when viewed as described above) to OUT (switch lever away from the battery connector). The IN position is used for charging the battery from an external 5VDC, >=600 mA source.
The charging current is 500 mA, so I recommend a battery with at least 500 mAH of capacity to avoid charging at a rate >1C.
A rough English translation of the charging process is as follows:
- Set the mode switch to OUT (switch lever away from the battery connector);
- Plug in the battery;
- Plug in the external 5VDC power supply (at least a 600 mA supply recommended);
- Set the mode switch to IN (switch lever toward the battery connector);
- When charging is complete as indicated by all 4 LEDs on, set the mode switch to OUT (switch lever away from the battery connector);
- Unplug the external 5VDC power supply.
The LED indications seem to be as follows, based on how Google Translate translates the Chinese datasheet for the HOTCHIP HT4901 at
[1]
Discharge Mode
Voltage LED1 LED2 LED3 LED4
3.2-3.5V ON OFF OFF OFF
3.5-3.65V ON ON OFF OFF
3.65-3.95V ON ON ON OFF
> 3.95V ON ON ON ON
If the voltage drops below 3.2V, LED1 flashes and within 5 seconds the HT4901 goes to standby mode (I think... or should I say I hope...) to avoid over-discharging your battery.
Charge Mode
Voltage LED1 LED2 LED3 LED4
<3.4V FLASH FLASH FLASH FLASH
3.4-3.8V ON FLASH FLASH FLASH
3.8-4.0V ON ON FLASH FLASH
4.0-4.25V ON ON ON FLASH
>= 4.25V ON ON ON ON
Be prepared to terminate the charging process immediately when all four LEDs are on and steady. Overcharging lithium-type batteries may result in a nasty fire. I don't know how good the HT4901 is at detecting that the charging process is complete and shutting off the charging current to the battery.
Hope I correctly translated this information. /Chip
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Pictures
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History
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