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Microduino-BM is a discharge module which combines a single-cell Li-ion battery charge management,
power detection and LED indication. The output voltage is 5V, and LDO is 3.3V output. Provides the outstanding battery management for the Microduino-Core module.
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Features
- Integrated functions that charge/discharge management, power detection, 5v output, 3.3v LDO;
- DIP switch controls the charging and discharging, reboot and sleep mode;
- Small, cheap, stackable, opened platform;
- Define unified interface Microduino specification and contain rich peripheral modules. Make up the quick connection with other Microduino modules and sensors easily and flexibly.
- 2.54 pitch row female connector for easy integration into breadboard.
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Specifications
Interfaces
- A key switch
- A two toggle switchs
- One pair of 2.54 battery interface ("+" for positive, "-" for negative)
- UPIN27 contains the 5V, 3V3, GND interface:
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Charging
- Firstly connect external 5V power , and then set the DIP switch to "IN" position, the module goes into the charging state, then four LED lights do Surge charging indication (detailed display mode, please refer to HT4901 document), the maximum charging current is 500mA. Finished charging,turn the DIP switch to "OUT", and unplug the external 5V charging power.
- Note:
- Always follow the charging process: make sure switch to OUT, plug in the battery, connect external 5V power, switch to IN, start charging, charging completed, switch to OUT, unplug the external 5V Charge power.
- Recommended charging power supply: Voltage 5v, current 600ma above;
- Don't add pressure drop elements (such as diodes) in the charging circuit, which impacts the charging current because of lower charging voltage.
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Discharge
- Make sure the switch is in the "OUT" firstly. After access to the battery, the module is in the standby mode, then short press button switch (timer> 50mS), the module will be wake up from standby mode. Voltage output will start at this time, and open UPIN27's GND circuit: Interface 5V outputs 5V voltage, maximum current is 500mA; while 3.3V interface outputs 3.3V voltage, maximum current is 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 the boost output;
- please do not toggle the 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. The four LEDs use to battery indicator, and last 3 ~ 5S.
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Standby
- Standby means that disconnect the circuit UPIN27's GND circuit. In this state, BM can be controlled within the overall power consumption of 30uA.
- Make sure the switch is in the "OUT", if no any action after accessing the battery, then the default mode is in standby mode.
- If you've turned on discharge mode,, pressing the button switch (3s above) to re-enter into standby mode.
- Intelligent Detection: No charge input, no discharge output (<10mA) within three minutes will enter 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
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
http://www.hotchip.com.cn/DownFiles/20131126090806453.pdf
Discharge Mode
| Voltage
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LED1
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LED2
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LED3
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LED4
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| 3.2-3.5V
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ON
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OFF
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OFF
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OFF
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| 3.5-3.65V
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ON
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ON
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OFF
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OFF
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| 3.65-3.95V
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ON
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ON
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ON
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OFF
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| > 3.95V
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ON
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ON
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ON
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ON
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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
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LED1
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LED2
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LED3
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LED4
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| <3.4V
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FLASH
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FLASH
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FLASH
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FLASH
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| 3.4-3.8V
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ON
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FLASH
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FLASH
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FLASH
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| 3.8-4.0V
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ON
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ON
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FLASH
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FLASH
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| 4.0-4.25V
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ON
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ON
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ON
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FLASH
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| >= 4.25V
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ON
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ON
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ON
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ON
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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
November 14, 2013 new release, major improvements:
- Canceled VMOT pin, use the toggle switch directly use the 5V port switching charge and discharge;
- Boost button can fully control the boost, UPIN27 the GND loop off.
- March 13, 2013 Batch completed.
- March 1, 2013 20130202 edition model released, testing is no big problem.
- February 2, 2013, using mobile power ASIC chip, re-layout.
- December 31, 2012, released the test panels, the main problems are:
- No 5V output;
- Battery Interface leakage;
- No power display.
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