EKM035 LiPo charger 0.2-2A + DCDC 3.3/5V
Part.no: 41037489
EKM035 is a charger module for 1-cell 3.7V LiPo batteries with an added step-up/step-down DCDC converter to keep the output voltage at a fixed 3.3V or 5V (selectable with jumper).
The charger is powered via the USB-C connector or a different DC power supply (4.1 - 5.5V) via the two adjecent pins. The charge current can be set from 0.2A to 2A.
The battery can be disconnected by shorting the two pins marked "SW", which makes it easy to wire a power switch to the module.
The pins for VIN, VSEL, SW and VOUT are placed on a 2.54mm grid, which makes it possible to mount the entire module on prototyping boards.
Functions
- Charge and power with one module
- Adjustable charge current for different battery sizes
- Adjustable output voltage, 3.3V or 5V
- LEDs for charge and power
Specifications
- Supply voltage (charger): 4.1 - 5.5V
- Charge current: 0.2 - 2.0V
- Supply voltage (DCDC converter): 1.8 - 5.5V
- Output current (step-up): 1.2A (2A max)
- Output current (step-down): 2A (3A max)
- Dimensions: 40 x 16 x 7.15mm
Connections
Supply voltage
The module can be powered via the USB-C connector with a nominal voltage of 5V. Wires can also be soldered to the adjecent holes marked + and -.
Please note! Do not connect two sources simultaneously!
The voltage range for the charger and converter are different, but the upper limit is 5.5V for both ICs. For the charger IC, the lowest supply voltage is 4.1V, under which charging stops. The DCDC converter however works down to 1.8V.
The module has no reverse polarity or over voltage protection, so be careful when connecting an external power supply to the module!
Battery
The battery connector is a JST-PH 2.0mm header and fits most small 1-cell LiPo batteries. Our complete range of compatible batteries are found here.
Output voltage
The connections for the output voltage will fit either a 3.5mm screw terminal, 2.54mm headers or wires soldered directly to the board.
Voltage selector
Two different output voltages can be selected by letting the VSEL pins be left open (5V), or shorting them (3.3V).
The DCDC converter will, automatically and without interruption, change from stepping up or stepping down the input voltage. It will keep the output voltage steady regardless of the input voltage.
Please note that the output current is lower when working in step-up or boost mode (such as when powered by battery and set to output 5V), than when working in step-down or buck mode (powered with 5V USB and set to 3.3V output).
Power switch
The module can be powered down by shorting the two VSEL pins. The power switch will disconnect the battery from the DCDC converter.
If the module is powered with an external source, the DCDC converter will still operate and provide power.
The battery is connected to the charger and DCDC converter when SW is left unconnected.
Charge current
The charge current for the connected battery can be adjusted by opening or shorting the solder jumpers A, B, C and D. Preset charge current is 0.2A (only D shorted).
Read the battery specifications before use and do not exceed the specified charge current.
| X = closed | D | C | B | A |
|---|---|---|---|---|
| 0.2A | X | |||
| 0.4A | X | X | ||
| 0.8A | X | |||
| 1.2A | X | X | X | |
| 1.6A | X | X | ||
| 1.8A | X | X | X | |
| 2.0A | X | X | X | X |
Datasheet
Mechanical dimensions
