USB Rechargeable LED Circuit

USB Rechargeable LED circuit designed for longer glowing time. This circuit has USB C Receptacle hence we can charge this circuit battery easily. LiPo (Lithium polymer) 3.7V, 500mAH battery used in this prototype circuit, you can use lower current rating Li-Po battery also. We can directly remove and connect LiPo battery with this circuit through JST connector.




This USB Rechargeable LED circuit has three white LEDs, due to the low power LEDs consumption this circuit gives longer duration glowing time. Hence it can be used as Rechargeable LED mini emergency light circuit.

Circuit Diagram

Components Required (BOM)

1C1, C2, C34.7µFC_0805_2012Metric3
2C42.2µFC_0805_2012Metric1
3R4, R55.1KΩR_0805_2012Metric2
4R12KΩR_0805_2012Metric1
5R2470ΩR_0805_2012Metric1
6R31.5KΩR_0805_2012Metric1
7L16.8µHL_6.3×6.3_H31
8D81N4007D_1206_3216Metric1
9D3ZHCS400TAD_SOD-3231
10D2LED-GLED_0805_2012Metric1
11D4, D5, D6LEDLED_1206_3216Metric_Castellated3
12U1MCP73831-2-OTSOT-23-51
13U2LT1932SOT-23-61
14BT13.7v 500mah li-poJST_EH_B02B-EH-A_1x02_P2.50mm_Vertical1
15S1JS102011SAQNSW_JS102011SAQN1
16J1105450-0101MOLEX_105450-01011

Construction & Working

This circuit has Regulator & charger section, then battery and then LED driver section. Power supply is taken from the USB C connector VBus and GND terminals and then IC MCP73831/2 miniature single cell fully integrated li-Ion, li-Polymer charge management controller Regulates the power supply and gives output voltage as 4V and output current as 500mA, you can program this IC to give different range of output current by changing Resistor value at PROG pin, refer data sheet for more details.

A slide switch S1 (SPDT SMD) connects battery with LED driver circuit section. Through this switch power supply flows to the LED driver IC LT1932, it is a constant current DC / DC LED driver in thin SOT package. It drives the output white LED devices. If you need high luminance then choose high power white LEDs, don’t forget to change the footprint in PCB files and bill of materials.

Printed Circuit Board (PCB)

USB Rechargeable LED Circuit PCB Gerber files.

Interactive Board Viewer

     




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