# 12V SEPIC Converter ## Description 4-layer 9–15 V input SEPIC converter producing regulated 12 V at up to 1.5 A, using IRLZ44N MOSFET, SS34 Schottky diode, separate 100 µH inductors, and thermal-via PCB layout for EV battery-management student project. ## Project Details - **Owner:** draco1738 - **Created:** 5/27/2026 - **Last Updated:** 5/28/2026 - **Visibility:** Public ## Key Components ### CCOMP — Generic Capacitor - Capacitance: 100pF - Role Details: Series compensation capacitor from COMP network to ground; user-specified value requires loop validation. - Voltage Rating: 50V - Role: Feedback - Part Type: Non-Polarized Capacitor - Package: SMD_0603_1608Metric **Pins:** - P1 [pin 1] - P2 [pin 2] ### CFF — Generic Capacitor - Part Type: Non-Polarized Capacitor - Package: SMD_0603_1608Metric - Capacitance: 10pF - Voltage Rating: 50V - Role Details: Optional feed-forward capacitor in parallel with top feedback resistor. - Role: Filtering **Pins:** - P1 [pin 1] - P2 [pin 2] ### CIN1 — Generic Capacitor - Capacitance: 10uF - Voltage Rating: 25V - Role Details: Part of parallel input capacitor bank, placed close to U1 VIN/SW loop. - Role: Bulk - Part Type: Non-Polarized Capacitor - Package: SMD_1210_3225Metric **Pins:** - P1 [pin 1] - P2 [pin 2] ### CIN2 — Generic Capacitor - Voltage Rating: 25V - Role: Bulk - Capacitance: 10uF - Package: SMD_1210_3225Metric - Part Type: Non-Polarized Capacitor - Role Details: Part of parallel input capacitor bank for effective >=25uF target. **Pins:** - P1 [pin 1] - P2 [pin 2] ### CIN3 — Generic Capacitor - Part Type: Non-Polarized Capacitor - Role: Bulk - Package: SMD_1210_3225Metric - Capacitance: 10uF - Voltage Rating: 25V - Role Details: Part of parallel input capacitor bank for effective >=25uF target. **Pins:** - P1 [pin 1] - P2 [pin 2] ### CINHF — Generic Capacitor - Voltage Rating: 50V - Capacitance: 100nF - Package: SMD_0603_1608Metric - Role: Decoupling - Role Details: High-frequency bypass placed close to U1 VIN and ground pins. - Part Type: Non-Polarized Capacitor **Pins:** - P1 [pin 1] - P2 [pin 2] ### COUT1 — Generic Capacitor - Part Type: Non-Polarized Capacitor - Package: SMD_1210_3225Metric - Capacitance: 10uF - Role: Bulk - Voltage Rating: 25V - Role Details: Part of output capacitor bank at 12V output; placed near output connector and diode cathode. **Pins:** - P1 [pin 1] - P2 [pin 2] ### COUT2 — Generic Capacitor - Package: SMD_1210_3225Metric - Part Type: Non-Polarized Capacitor - Role: Bulk - Voltage Rating: 25V - Role Details: Part of output capacitor bank at 12V output for effective >=25uF target. - Capacitance: 10uF **Pins:** - P1 [pin 1] - P2 [pin 2] ### COUT3 — Generic Capacitor - Part Type: Non-Polarized Capacitor - Role Details: Part of output capacitor bank at 12V output for effective >=25uF target. - Role: Bulk - Package: SMD_1210_3225Metric - Capacitance: 10uF - Voltage Rating: 25V **Pins:** - P1 [pin 1] - P2 [pin 2] ### CSEP1 — Generic Capacitor - Voltage Rating: 25V - Capacitance: 10uF - Package: SMD_1210_3225Metric - Role Details: Part of 30uF SEPIC series coupling capacitor bank; high RMS ripple current path. - Role: Coupling - Part Type: Non-Polarized Capacitor **Pins:** - P1 [pin 1] - P2 [pin 2] ### CSEP2 — Generic Capacitor - Part Type: Non-Polarized Capacitor - Package: SMD_1210_3225Metric - Capacitance: 10uF - Role: Coupling - Voltage Rating: 25V - Role Details: Part of 30uF SEPIC series coupling capacitor bank; high RMS ripple current path. **Pins:** - P1 [pin 1] - P2 [pin 2] ### CSEP3 — Generic Capacitor - Role: Coupling - Voltage Rating: 25V - Capacitance: 10uF - Role Details: Part of 30uF SEPIC series coupling capacitor bank; high RMS ripple current path. - Package: SMD_1210_3225Metric - Part Type: Non-Polarized Capacitor **Pins:** - P1 [pin 1] - P2 [pin 2] ### CSS — Generic Capacitor - Role Details: Programs TPS55340 soft-start time from SS pin to AGND. - Role: Soft Start - Voltage Rating: 50V - Capacitance: 10nF - Package: SMD_0603_1608Metric - Part Type: Non-Polarized Capacitor **Pins:** - P1 [pin 1] - P2 [pin 2] ### D1 — [SS34](https://www.flux.ai/lcsc/ss34~6q67.md) - Package or Case Code: SMB_L4.3-W3.6-LS5.4-RD - Manufacturer Part Number: SS34 - Manufacturer Name: UMW(友台半导体) - Part Type: Schottky Barrier Diodes (SBD) - LCSC Part Number: C2758511 - Reverse Voltage: 40V - Datasheet URL: https://www.lcsc.com/datasheet/C2758511.pdf - JLCPCB Part Class: Extended Part - Role Details: 3A 40V Schottky diode; anode to SW node and cathode to regulated 12V output. - Role: Rectification - Forward Voltage: 0.3V to 0.45V - Diode Type: Schottky **Pins:** - A [pin 2] - K [pin 1] ### J1 — [31059102](https://www.flux.ai/adrian95/31059102~ga.md) - Package or Case Code: CONN_31059102_MZC - Role: Power Conversion - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector - Role Details: 2-pin 3.5mm through-hole terminal block for 9-15V input; current path budget is 2.47A worst-case. - Datasheet URL: https://www.metz-connect.com/html/overlay:service:download.en.html?filepath=db%3Aproducts%2Fdocid%3A8a8a80ea8ab0bf64018afc46d8e22b35.de.1&fileurl=310591%2F863248.PDF - Manufacturer Part Number: 31059102 - Manufacturer Name: METZ CONNECT USA Inc. **Pins:** - 1 [pin 1] - 2 [pin 2] ### J2 — [31059102](https://www.flux.ai/adrian95/31059102~ga.md) - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Package or Case Code: CONN_31059102_MZC - Role Details: 2-pin through-hole terminal block for regulated 12V output up to 1.5A. - Role: Power Conversion - Manufacturer Name: METZ CONNECT USA Inc. - Manufacturer Part Number: 31059102 - Datasheet URL: https://www.metz-connect.com/html/overlay:service:download.en.html?filepath=db%3Aproducts%2Fdocid%3A8a8a80ea8ab0bf64018afc46d8e22b35.de.1&fileurl=310591%2F863248.PDF **Pins:** - 1 [pin 1] - 2 [pin 2] ### RCOMP — [Generic Resistor](https://www.flux.ai/jharwinbarrozo/generic-resistor~3e.md) - Role Details: Series compensation resistor in COMP network; user-specified value requires loop validation. - Part Type: Resistor - Tolerance: 1% - Resistance: 10kΩ - Package: SMD_0805_2012Metric - Role: Feedback **Pins:** - P1 [pin 1] - P2 [pin 2] ### REN — [Generic Resistor](https://www.flux.ai/jharwinbarrozo/generic-resistor~3e.md) - Role: Pull Up / Down - Role Details: Pulls EN to VIN so converter is enabled whenever input power is present. - Package: SMD_0805_2012Metric - Part Type: Resistor - Tolerance: 1% - Resistance: 100kΩ **Pins:** - P1 [pin 1] - P2 [pin 2] ### RFBB — [Generic Resistor](https://www.flux.ai/jharwinbarrozo/generic-resistor~3e.md) - Role: Feedback - Package: SMD_0805_2012Metric - Role Details: Bottom divider resistor from FB node to AGND for 12V regulation. - Tolerance: 1% - Resistance: 10kΩ - Part Type: Resistor **Pins:** - P1 [pin 1] - P2 [pin 2] ### RFBT — [Generic Resistor](https://www.flux.ai/jharwinbarrozo/generic-resistor~3e.md) - Role Details: Top divider resistor for TPS55340 1.229V reference, targets ~12V output. - Package: SMD_0805_2012Metric - Part Type: Resistor - Resistance: 87.6kΩ - Tolerance: 1% - Role: Feedback **Pins:** - P1 [pin 1] - P2 [pin 2] ### RFREQ — [Generic Resistor](https://www.flux.ai/jharwinbarrozo/generic-resistor~3e.md) - Resistance: 142kΩ - Tolerance: 1% - Part Type: Resistor - Role: Timing - Package: SMD_0805_2012Metric - Role Details: FREQ-to-AGND resistor calculated from TPS55340 datasheet for ~340kHz; replaces user 75k value which is inconsistent with datasheet equation. **Pins:** - P1 [pin 1] - P2 [pin 2] ### TP_FB — [5003](https://www.flux.ai/lcsc/5003~2fut.md) - Manufacturer Part Number: 5003 - Part Type: Test Points/Test Rings - Manufacturer Name: Keystone - JLCPCB Part Class: Extended Part - LCSC Part Number: C238124 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2409302136_Keystone-5003_C238124.pdf - Package or Case Code: TEST-TH_BD2.54-P1.39 - Product Info Url: https://lcsc.com/product-detail/Test-Points-Test-Rings_Keystone_5003_Keystone-5003_C238124.html **Pins:** - 1 [pin 1] ### TP_GND — [5003](https://www.flux.ai/lcsc/5003~2fut.md) - Manufacturer Part Number: 5003 - Part Type: Test Points/Test Rings - Manufacturer Name: Keystone - JLCPCB Part Class: Extended Part - LCSC Part Number: C238124 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2409302136_Keystone-5003_C238124.pdf - Package or Case Code: TEST-TH_BD2.54-P1.39 - Product Info Url: https://lcsc.com/product-detail/Test-Points-Test-Rings_Keystone_5003_Keystone-5003_C238124.html **Pins:** - 1 [pin 1] ### TP_SW — [5003](https://www.flux.ai/lcsc/5003~2fut.md) - JLCPCB Part Class: Extended Part - LCSC Part Number: C238124 - Manufacturer Part Number: 5003 - Manufacturer Name: Keystone - Part Type: Test Points/Test Rings - Package or Case Code: TEST-TH_BD2.54-P1.39 - Product Info Url: https://lcsc.com/product-detail/Test-Points-Test-Rings_Keystone_5003_Keystone-5003_C238124.html - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2409302136_Keystone-5003_C238124.pdf **Pins:** - 1 [pin 1] ### TP_VIN — [5003](https://www.flux.ai/lcsc/5003~2fut.md) - JLCPCB Part Class: Extended Part - LCSC Part Number: C238124 - Manufacturer Part Number: 5003 - Part Type: Test Points/Test Rings - Manufacturer Name: Keystone - Package or Case Code: TEST-TH_BD2.54-P1.39 - Product Info Url: https://lcsc.com/product-detail/Test-Points-Test-Rings_Keystone_5003_Keystone-5003_C238124.html - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2409302136_Keystone-5003_C238124.pdf **Pins:** - 1 [pin 1] ### TP_VOUT — [5003](https://www.flux.ai/lcsc/5003~2fut.md) - Part Type: Test Points/Test Rings - Manufacturer Name: Keystone - Manufacturer Part Number: 5003 - LCSC Part Number: C238124 - JLCPCB Part Class: Extended Part - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2409302136_Keystone-5003_C238124.pdf - Product Info Url: https://lcsc.com/product-detail/Test-Points-Test-Rings_Keystone_5003_Keystone-5003_C238124.html - Package or Case Code: TEST-TH_BD2.54-P1.39 **Pins:** - 1 [pin 1] ### U1 — [TPS55340RTER](https://www.flux.ai/lcsc/tps55340rter~mt7l.md) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2410122030_Texas-Instruments-TPS55340RTER_C169167.pdf - Role: Power Conversion - JLCPCB Part Class: Extended Part - Manufacturer Part Number: TPS55340RTER - Output Current: 5.25A - Frequency: 100kHz~1.2MHz - Manufacturer Name: TI(德州仪器) - Part Type: DC-DC Converters - LCSC Part Number: C169167 - Role Details: TPS55340 integrated 5A/40V switch used for 9-15V to 12V SEPIC; exact RGER/VQFN-20 part not available in Flux library, RTER WQFN-16 used. - Product Info Url: https://lcsc.com/product-detail/DC-DC-Converters_TI_TPS55340RTER_TPS55340RTER_C169167.html - Max Input Voltage: 32V - Package or Case Code: VQFN-16_L3.0-W3.0-P0.50-BL-EP1.7 - Operating Temperature: -40℃~+150℃ **Pins:** - AGND [pin 6] - COMP [pin 7] - EN [pin 3] - EP [pin 17] - FB [pin 8] - FREQ [pin 9] - NC [pin 14] - NC [pin 10] - PGND [pin 11] - PGND [pin 13] - PGND [pin 12] - SS [pin 4] - SW [pin 16] - SW [pin 15] - SW [pin 1] - SYNC [pin 5] - VIN [pin 2] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/draco1738/12v-sepic-converter~jo](https://www.flux.ai/draco1738/12v-sepic-converter~jo).* --- *Generated from [https://www.flux.ai/draco1738/12v-sepic-converter~jo](https://www.flux.ai/draco1738/12v-sepic-converter~jo)*