2 layers75.8 × 18 mm
3S coinHolder LIR1254
PocketConcepts/Pocket_PSU
A variable current & voltage PSU with 3S lipo charging, balancing, and protection circuit using PPS.
6 parts36
2 layers75.8 × 19.2 mm
3S coinCellChargeController
PocketConcepts/Pocket_PSU36A variable current & voltage PSU with 3S lipo charging, balancing, and protection circuit using PPS.
- Size
- 75.8 × 19.2 mm
- Copper layers
- 2
- Thickness
- 0.79 mm
- Parts
- 78
- Nets
- 62
- Pads
- 232
- Tracks, vias
- 350, 124
- Pours
- 11
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 19 Nov 2025
- Updated
- 19 Nov 2025
Overview
3S coinCellChargeController is an open-source printed circuit board by PocketConcepts, from the PocketConcepts/Pocket_PSU repository on GitHub. It is a 2-layer board of 75.8 × 19.2 mm with 78 parts on 62 nets, routed with 350 tracks and 124 vias.
It is built around the ATTINY402-SSN, BQ25792RQMR and S-8254AAWFT-TB-G, with the DMG2301L, 103AT-2 and CD0603-B0240R among its other parts. Its parts include 26 resistors, 25 capacitors, 9 connectors, 4 ICs and 4 diodes. It belongs with the power boards and the AVR (ATmega, ATtiny) boards of this library.
Main components
10
ATTINY402-SSN
SOIC-8-40℃~+105℃ 1.8V~5.5V 10bit 128Byte 20MHz 256Byte 4KB 6 8 Bit AVR Built-in FLASH SOIC-8 Microcontrollers (MCU/MPU/SOC) ROHSMicrochip TechnologyMicrocontrollers (MCU/MPU/SOC)
BQ25792RQMR
QFN-29(4x4)-40℃~+85℃ 16.8V 1~4 21uA 3.6V~24V 5A Charging IC I2C Lithium Battery Support QFN-29(4x4) Battery Management ROHSTexas InstrumentsBattery Management
S-8254AAWFT-TB-G
TSSOP-16-40℃~+85℃ 2V~24V 3.2V 3~4 4.2V TSSOP-16 Battery Management ROHSABLICBattery Management
DMG2301L
SOT-23-55℃~+150℃ 1 P-Channel 1.2V 1.5W 150mΩ@2.5V 20V 3A 5.5nC@4.5V P-Channel SOT-23 MOSFETs ROHSDiodes IncorporatedMOSFETs
103AT-2
ThroughholeThroughhole NTC Thermistors ROHSSEMITECNTC Thermistors
CD0603-B0240R
0603-40℃~+125℃ 1 Independent 1uA@10V 200mA 2A 40V 550mV@200mA 0603 Schottky Diodes ROHSBournsSchottky Diodes
ESDA25P35-1U1M
DFN1610-2-55℃~+150℃ 1 1.4kW@8/20us 200nA 22V 24.6V 35A@8/20us 41V IEC 61000-4-2 TVS Unidirectional DFN1610-2 ESD and Surge Protection (TVS/ESD) ROHSSTMicroelectronicsESD And Surge Protection (TVS/ESD)MMBT3904
SOT-23-55℃~+150℃ 1 NPN 100 100nA 200mA 200mW 300MHz 300mV 40V 6V NPN SOT-23 Bipolar (BJT) ROHSJiangsu Changjing Electronics Technology (CJ)Bipolar (BJT)
SLLB510100
SMDSMD Multi-Directional Switches ROHSALPSALPINEMulti-Directional SwitchesUJC-H-G-SMT-2-P6-TR
SMDSMD USB Connectors ROHSCUIUSB Connectors
README
README.mdPocket_PSU
A variable current & voltage PSU with 3S lipo charging, balancing, and protection circuit using PPS.
For times where you just wish you could carry a mini bench PSU in your pocket...
Safely charge from any USB C source, and delivery 2.8V - 22V at 0.12A - 3A.
Parts
78| Qty | Value | Footprint | References |
|---|---|---|---|
| 9 | 10k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R4, R5, R6, R8, R10, R12, R20, R21, R24 |
| 8 | 100n | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | C12, C13, C15, C16, C17, C20, C21, C22 |
| 5 | 100n | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C1, C3, C6, C7, C8 |
| 4 | 1k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R11, R14, R15, R16 |
| 4 | Conn_01x01_Socket | TestPoint:TestPoint_Pad_2.5x2.5mm | J6, J7, J8, J9 |
| 3 | 100k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R25, R26, R28 |
| 3 | DMG2301L | Package_TO_SOT_SMD:SOT-23 | Q1, Q2, Q4 |
| 2 | 10u | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C5, C9 |
| 2 | 10u | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | C14, C14 |
| 2 | 2.2u | Capacitor_SMD:C_0805_2012Metric | C18, C19 |
| 2 | 47n | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C10, C11 |
| 2 | 5.1k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R17, R18 |
| 1 | 100 | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R2 |
| 1 | 103AT-2 | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | TH1 |
| 1 | 10R | Resistor_SMD:R_0603_1608Metric | R13 |
| 1 | 10u | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C4 |
| 1 | 120mR | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R_OCP1 |
| 1 | 13.7k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R3 |
| 1 | 1M | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R7 |
| 1 | 1u | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C24 |
| 1 | 2.2u | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C23 |
| 1 | 2.2uH | Inductor_SMD:L_Vishay_IHLP-1212 | L1 |
| 1 | 22R | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R27 |
| 1 | 4.7u | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C2 |
| 1 | 4k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R1 |
| 1 | 4k7 | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R22 |
| 1 | 630R | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R23 |
| 1 | ATtiny402-SS | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U3 |
| 1 | BQ25792RQMR | BQ25792RQMR:QFN40P400X400X100-29N | U1 |
| 1 | CD0603-B0240R | Capacitor_SMD:C_0603_1608Metric | D3 |
| 1 | Conn_01x02_Pin | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J1 |
| 1 | Conn_01x03_Pin | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J4 |
| 1 | Conn_01x04_Pin | Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_Vertical | J2 |
| 1 | Conn_01x04_Socket | Connector_PinSocket_2.54mm:PinSocket_1x04_P2.54mm_Vertical | J5 |
| 1 | ESDA25P35-1U1M | Diode_SMD:D_0603_1608Metric_Pad1.05x0.95mm_HandSolder | D2 |
| 1 | LED | LED_SMD:LED_0603_1608Metric_Pad1.05x0.95mm_HandSolder | D1 |
| 1 | LED | Diode_SMD:D_0603_1608Metric_Pad1.05x0.95mm_HandSolder | D4 |
| 1 | MMBT3904 | Package_TO_SOT_SMD:SOT-23 | Q3 |
| 1 | NCP718xSN500 | Package_TO_SOT_SMD:SOT-23-5 | U4 |
| 1 | NetTie_2 | NetTie:NetTie-2_SMD_Pad0.5mm | NT1 |
| 1 | S-8254AAWFT-TB-G | S-8254AAVFT-TB-G:SOP65P640X110-16N | U2 |
| 1 | SLLB510100 | SLLB510100:SLLB510100 | SW1 |
| 1 | SLW-66527511-SMT-TR | SLW-66527511-SMT-TR:SW_SLW-66527511-SMT-TR | S1 |
| 1 | UJC-H-G-SMT-2-P6-TR | UJC-H-G-SMT-2-P6-TR:SAMESKY_UJC-H-G-SMT-2-P6-TR | J3 |
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Questions
How big is the 3S coinCellChargeController PCB?
It measures 75.8 × 19.2 mm and has 2 copper layers, 0.79 mm thick.
What parts does the 3S coinCellChargeController use?
78 parts, built around the ATTINY402-SSN, BQ25792RQMR, S-8254AAWFT-TB-G and DMG2301L. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the 3S coinCellChargeController KiCad files?
From the PocketConcepts/Pocket_PSU repository on GitHub, at the commit this page was made from: the board is HW/3S_coinCellChargeController/3S_coinCellChargeController.kicad_pcb and its schematic HW/3S_coinCellChargeController/3S_coinCellChargeController.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the 3S coinCellChargeController design in my own project?
Its repository states no licence, so its author keeps all rights: ask PocketConcepts before reusing the design.