# STM32G4 Digital CC-CV Buck Converter ## Description Digitally controlled 24 V to 0-12 V 1 A buck converter with STM32G4 MCU, CC/CV regulation, SWD debug, SPI expansion connectors, and placeholder power I/O connectors. ## Project Details - **Owner:** akashghosh931 - **Created:** 8/9/2025 - **Last Updated:** 3/28/2026 - **Visibility:** Public - **Implementation Details:** Architecture uses an analog buck power stage with STM32G4 digital supervisory control for programmable CC/CV behavior. Open items: final input/output connector naming, exact SPI role assignment, and firmware loop implementation details. Design target: 24V input, 0-12V output, 1A maximum load, BOM under $20, ripple within +/-10% for voltage and current. ## Key Components ### CN1 — [B2P-VH(LF)(SN)](https://www.flux.ai/lcsc/b2p-vhlfsn.md) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_JST-B2P-VH-LF-SN_C160315.pdf - Package or Case Code: CONN-TH_B2P-VH-LF-SN - Connector Type: Header - Part Type: Wire To Board / Wire To Wire Connector - LCSC Part Number: C160315 - Product Info Url: https://lcsc.com/product-detail/_JST_B2P-VH-LF-SN_B2P-VH-LF-SN_C160315.html - JLCPCB Part Class: Extended Part - Connector Gender: Male - Role Details: 24V input power connector rated well above 1A load current for buck input feed - Voltage Rating: 250V - Manufacturer Part Number: B2P-VH(LF)(SN) - Connector Pitch: 3.96mm - Operating Temperature: -25 ~ +85℃ - Connector Rows: 1 - Current Rating: 10A - Role: Power Connector - Package: THT 3.96mm Header - Manufacturer Name: JST - Connector Positions: 2 **Pins:** - 1 [pin 1] - 2 [pin 2] ### CN2 — [B2P-VH(LF)(SN)](https://www.flux.ai/lcsc/b2p-vhlfsn.md) - Operating Temperature: -25 ~ +85℃ - Package: THT 3.96mm Header - Connector Rows: 1 - Current Rating: 10A - Manufacturer Name: JST - Connector Positions: 2 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_JST-B2P-VH-LF-SN_C160315.pdf - Package or Case Code: CONN-TH_B2P-VH-LF-SN - Role Details: 0-12V regulated output connector rated above 1A continuous output current - Connector Type: Header - Product Info Url: https://lcsc.com/product-detail/_JST_B2P-VH-LF-SN_B2P-VH-LF-SN_C160315.html - LCSC Part Number: C160315 - Part Type: Wire To Board / Wire To Wire Connector - JLCPCB Part Class: Extended Part - Connector Gender: Male - Voltage Rating: 250V - Manufacturer Part Number: B2P-VH(LF)(SN) - Role: Power Connector - Connector Pitch: 3.96mm **Pins:** - 1 [pin 1] - 2 [pin 2] ### D1 — [SMBJ24A-TR](https://www.flux.ai/lcsc/smbj24a-tr.md) - JLCPCB Part Class: Extended Part - Package: SMB - Package or Case Code: SMB_L4.6-W3.6-LS5.3-RD - Role: Input TVS - Manufacturer Name: ST(意法半导体) - Part Type: TVS - Manufacturer Part Number: SMBJ24A-TR - Product Info Url: https://lcsc.com/product-detail/TVS_STMicroelectronics_SMBJ24A-TR_SMBJ24A-TR_C133668.html - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_STMicroelectronics-SMBJ24A-TR_C133668.pdf - Role Details: Transient suppression on 24V input connector for surge and ESD robustness - LCSC Part Number: C133668 **Pins:** - A [pin 2] - K [pin 1] ### J1 — [TSW-103-07-G-D](https://www.flux.ai/adrian95/tsw-103-07-g-d.md) - Datasheet URL: https://suddendocs.samtec.com/prints/tsw-xxx-xx-x-x-xx-xxx-footprint.pdf - Package: THT 2.54mm Header - Part Type: Connector - Manufacturer Name: Samtec Inc. - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Programming and debug connector carrying 3V3, SWDIO, SWCLK, GND, SWO, and NRST - Manufacturer Part Number: TSW-103-07-G-D - Role: SWD Header **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] - 5 [pin 5] - 6 [pin 6] ### J2 — [TSW-104-07-G-S](https://www.flux.ai/adrian95/tsw-104-07-g-s.md) - Package: THT 2.54mm Header - Datasheet URL: http://suddendocs.samtec.com/prints/tsw-xxx-xx-xxx-x-xx-xxx-mkt.pdf - Package or Case Code: TSW10407GS - Part Type: Connector - Role Details: 1x4 SPI header with dedicated MOSI, MISO, SCK, and NSS/CS signals - Manufacturer Part Number: TSW-104-07-G-S - Role: SPI Connector - Manufacturer Name: Samtec Inc. - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] ### Q1 — [AO3401A](https://www.flux.ai/jecstronic/ao3401a.md) - Role Details: P-channel MOSFET used as ideal-diode style input reverse-polarity protector - Part Type: Transistor - Package: SOT-23 - Datasheet URL: https://www.lcsc.com/datasheet/lcsc_datasheet_2007171935_HUASHUO-AO3401A_C700954.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: AO3401A - Manufacturer Name: HUASHUO - Role: Reverse Polarity Protection **Pins:** - D [pin 3] - G [pin 1] - S [pin 2] ### SW1 — [TS-1088-AR02016](https://www.flux.ai/lcsc/ts-1088-ar02016.md) - Role: Reset Button - Package or Case Code: SW-SMD_L3.9-W3.0-P4.45 - JLCPCB Part Class: Extended Part - Manufacturer Part Number: TS-1088-AR02016 - Role Details: Momentary switch pulling NRST low for manual reset - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2409302330_XUNPU-TS-1088-AR02016_C720477.pdf - Manufacturer Name: XUNPU(讯普) - Package: SW-SMD_L3.9-W3.0-P4.45 - LCSC Part Number: C720477 - Part Type: Tactile Switches - Product Info Url: https://lcsc.com/product-detail/Tactile-Switches_XUNPU-TS-1088-AR02016_C720477.html **Pins:** - 1 [pin 1] - 2 [pin 2] ### U1 — [STM32G431RBT6](https://www.flux.ai/lcsc/stm32g431rbt6.md) - JLCPCB Part Class: Extended Part - Role Details: STM32G4 MCU for digital CC/CV supervision, telemetry, PWM control, and SPI/SWD interfaces - Manufacturer Part Number: STM32G431RBT6 - LCSC Part Number: C431633 - Package: LQFP-64 - Part Type: ST Microelectronics - Role: Digital Controller - Package or Case Code: LQFP-64_L10.0-W10.0-P0.50-LS12.0-BL - Manufacturer Name: ST(意法半导体) - Implementation Details: Unused GPIO and oscillator-capable pins are intentionally reserved for future firmware and hardware expansion; leave unbonded in current revision and treat as intentional no-connects during review. - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/1912111437_STMicroelectronics-STM32G431RBT6_C431633.pdf - Product Info Url: https://lcsc.com/product-detail/New-Arrivals_STMicroelectronics-STM32G431RBT6_C431633.html **Pins:** - PA0 [pin 12] - PA1 [pin 13] - PA10 [pin 44] - PA11 [pin 45] - PA12 [pin 46] - PA13 [pin 49] - PA14 [pin 50] - PA15 [pin 51] - PA2 [pin 14] - PA3 [pin 17] - PA4 [pin 18] - PA5 [pin 19] - PA6 [pin 20] - PA7 [pin 21] - PA8 [pin 42] - PA9 [pin 43] - PB0 [pin 24] - PB1 [pin 25] - PB10 [pin 30] - PB11 [pin 33] - PB12 [pin 34] - PB13 [pin 35] - PB14 [pin 36] - PB15 [pin 37] - PB2 [pin 26] - PB3 [pin 56] - PB4 [pin 57] - PB5 [pin 58] - PB6 [pin 59] - PB7 [pin 60] - PB8-BOOT0 [pin 61] - PB9 [pin 62] - PC0 [pin 8] - PC1 [pin 9] - PC10 [pin 52] - PC11 [pin 53] - PC12 [pin 54] - PC13 [pin 2] - PC14-OSC32_IN [pin 3] - PC15-OSC32_OUT [pin 4] - PC2 [pin 10] - PC3 [pin 11] - PC4 [pin 22] - PC5 [pin 23] - PC6 [pin 38] - PC7 [pin 39] - PC8 [pin 40] - PC9 [pin 41] - PD2 [pin 55] - PF0-OSC_IN [pin 5] - PF1-OSC_OUT [pin 6] - PG10-NRST [pin 7] - VBAT [pin 1] - VDD [pin 48] - VDD [pin 32] - VDD [pin 64] - VDD [pin 16] - VDDA [pin 29] - VREF+ [pin 28] - VSS [pin 15] - VSS [pin 31] - VSS [pin 47] - VSS [pin 63] - VSSA [pin 27] ### U2 — [TPS56339DDC](https://www.flux.ai/kicad-part-library/tps56339ddc.md) - Package: SOT-23-6 - Manufacturer Part Number: TPS56339DDC - Datasheet URL: https://www.ti.com/lit/ds/symlink/tps56339.pdf - Manufacturer Name: Texas Instruments Inc. - Role: Buck Regulator - Package or Case Code: SOT-23-6 - Role Details: 24V to 0-12V programmable buck stage under STM32 supervisory control **Pins:** - BOOT [pin 6] - EN [pin 5] - FB [pin 4] - GND [pin 1] - SW [pin 2] - VIN [pin 3] ### U3 — [INA180A1](https://www.flux.ai/kicad-part-library/ina180a1.md) - Package: SOT-23-5 - Manufacturer Part Number: INA180A1 - Manufacturer Name: Texas Instruments Inc. - Role: Current Sense Amplifier - Datasheet URL: http://www.ti.com/lit/ds/symlink/ina180.pdf - Role Details: Amplifies shunt voltage for STM32 ADC current measurement - Package or Case Code: SOT-23-5 **Pins:** - - [pin 4] - + [pin 3] - ~ [pin 1] - GND [pin 2] - V+ [pin 5] ### U4 — [MCP1703Ax-330xxTT](https://www.flux.ai/kicad-part-library/mcp1703ax-330xxtt.md) - Manufacturer Name: Microchip Technology Inc. - Datasheet URL: http://ww1.microchip.com/downloads/en/DeviceDoc/20005122B.pdf - Role Details: Generates 3.3V logic rail from regulated buck output for MCU and analog sensing - Package or Case Code: SOT-23 - Manufacturer Part Number: MCP1703Ax-330xxTT - Role: 3.3V LDO - Package: SOT-23 **Pins:** - GND [pin 1] - VI [pin 3] - VO [pin 2] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/akashghosh931/stm32g4-digital-cc-cv-buck-converter](https://www.flux.ai/akashghosh931/stm32g4-digital-cc-cv-buck-converter).* --- *Generated from [https://www.flux.ai/akashghosh931/stm32g4-digital-cc-cv-buck-converter](https://www.flux.ai/akashghosh931/stm32g4-digital-cc-cv-buck-converter)*