Billing Control Unit (TCU) Reference Design
An illustrative reference design for the billing control unit (TCU) of DC chargers on the consumption / charging side of PV & ESS: the processor connects to the OCPP operations platform over Ethernet (dual port) and 4G, controls the charging modules and communicates with the vehicle BMS per GB/T 27930 over isolated CAN, and reads the DC energy meter (DL/T 645) for billing over isolated RS-485; 12 V comes from the charger's internal auxiliary supply. Each position is marked with the VOOHU parts available, recommended part numbers and package pinouts.
Illustrative PCB ⇄ Schematic
Illustrative top-side view arranged by functional zone (not the actual layout). Red numbered dots mark positions VOOHU can supply. Click a component on the board, an entry in the index below or a part in the schematic to see recommended parts and package pinouts on the right.
Illustrative Ethernet topology: the processor connects over RMII to the 10/100 switch IC U3 (JL5104C, 3 + 1 ports); each of the two downstream ports passes ESD D1 (WHALD03G4U) and the VOOHU high-isolation LAN transformer T1 (WHSH16F01D4, 4800 Vrms) to the 1×2 RJ45 J1; cable-side center taps go to chassis ground through 75Ω×2 + 1nF/2kV. Port P0 is drawn with one pair; the other port and the other pairs are identical.
Board bill of materials
Summarized by position; click any row to locate it on the board above.
| No. | Zone | Position | Ref. | VOOHU category | Recommended part | Availability |
|---|---|---|---|---|---|---|
| 01 | A Ethernet ×2 | RJ45 1×2 ports (platform / local) | J1 | RJ45 Connector | WH56I3288RGGG0121101 | VOOHU |
| 02 | A Ethernet ×2 | 10/100 LAN transformers ×2 (high isolation) | T1 | LAN Transformers | WHSH16F01D4 | VOOHU |
| 03 | A Ethernet ×2 | Ethernet port ESD array | D1 | TVS ESD | WHALD03G4U | VOOHU |
| 04 | A Ethernet ×2 | 10/100 switch IC (3 + 1 ports) | U3 | Ethernet Switch ICs | JL5104C-NI | VOOHU |
| 05 | B CAN ×2 (isolated) | CAN connectors ×2 (charging modules / vehicle BMS) | J2 | — | — | Non-VOOHU |
| 06 | B CAN ×2 (isolated) | CAN CMC ×2 | L1 | Signal Line Common Mode Chokes | WHAC-3225B-510U0 | VOOHU |
| 07 | B CAN ×2 (isolated) | CAN ESD / TVS ×2 | D2 | TVS ESD | WHALD30E2B | VOOHU |
| 08 | B CAN ×2 (isolated) | Isolated CAN transceivers ×2 | U4 | — | — | Non-VOOHU |
| 09 | B CAN ×2 (isolated) | Push-pull driver + rectifier / LDO | U5 | — | — | Non-VOOHU |
| 10 | B CAN ×2 (isolated) | Push-pull isolation transformer | T2 | Push-Pull Transformers | WHST06K02A0 | VOOHU |
| 11 | C Meter / 4G | Meter RS-485 terminal | J3 | — | — | Non-VOOHU |
| 12 | C Meter / 4G | RS-485 GDT | GDT1 | GDT | WHGT090V1P0A | VOOHU |
| 13 | C Meter / 4G | RS-485 CMC | L2 | Signal Line Common Mode Chokes | WHAC-4532A-510U0 | VOOHU |
| 14 | C Meter / 4G | RS-485 ESD / TVS | D3 | TVS ESD | WHALD30E2B | VOOHU |
| 15 | C Meter / 4G | Isolated RS-485 transceiver | U6 | — | — | Non-VOOHU |
| 16 | C Meter / 4G | Nano SIM card socket | J4 | SIM Card Sockets | WHNS135-T1151-01 | VOOHU |
| 17 | C Meter / 4G | SIM card ESD array | D4 | TVS ESD | WHTA5V01P2C | VOOHU |
| 18 | C Meter / 4G | 4G Cat.1 module | U7 | — | — | Non-VOOHU |
| 19 | D Processor | Processor (billing + OCPP) | U1 | — | — | Non-VOOHU |
| 20 | D Processor | eMMC | U2 | — | — | Non-VOOHU |
| 21 | E 12 V power | 12 V power input (in-charger auxiliary supply) | J5 | — | — | Non-VOOHU |
| 22 | E 12 V power | Input power-line common-mode choke | L3 | Power Line Common Mode Chokes | WHAL-7060A-102T0 | VOOHU |
| 23 | E 12 V power | Buck converter (12 V → 5 V / 4G 3.8 V) | U8 | — | — | Non-VOOHU |
| 24 | E 12 V power | Buck converter (5 V → 3.3 V / core) | U9 | — | — | Non-VOOHU |
| 25 | E 12 V power | Molded inductors ×2 (DC-DC) | L4 L5 | Molded Inductors | WHYT0630 Series | VOOHU |
Resources & downloads
Board bill of materials
Reference designators, zones, VOOHU categories, recommended parts and availability for all 25 positions. Opens directly in Excel.
Datasheet collection
Datasheet PDFs for the VOOHU parts recommended on this board.
Design files & footprint library
Schematic, PCB, and VOOHU part footprints and 3D models.
Coming soonRequest the billing control unit (TCU) reference design full package
Includes the full-board position list, datasheets for the recommended VOOHU parts and position-by-position selection notes. For selection advice tailored to your interface count, OCPP version or certification requirements, please include it in your requirements. We reply within 24 hours on working days.
