# Project Specification ## Project Overview - **Name:** EV Charge Controller Test Board - **Status:** Review-stage logical schematic only - **Purpose:** Programmable single-phase AC EV charging controller and test board for IEC/GB/T-style control-pilot and cable-coding experiments. - **Critical limitation:** This is **not production-ready** and **not safety-certified**. Do not claim compliance and do not generate final manufacturing files from this revision. ## Intended Use - Bench/review prototype for evaluating EVSE control behavior, CP generation/monitoring, CC/RC/S3 emulation, relay control, and output measurement. - External upstream RCD/MCB is assumed. - No RCD or MCB is included on this board. ## Required Hierarchical Sheets - TOP_LEVEL_INTERFACES - POWER_MCU_COMMUNICATION - CP_GENERATION_AND_MONITOR - CC_PP_RC_R4_AND_DISCHARGE_IDENTIFICATION - CHARGE_AND_DISCHARGE_CONTACTOR_CONTROL - AC_MAIN_PATH_AND_BIDIRECTIONAL_MEASUREMENT - REVIEW_AND_TEST_STATE_TABLE ## What the Device Should Do - Accept an external isolated 24 VDC control supply. - Generate IEC/GB/T-style 1 kHz CP signaling in normal and programmable test modes. - Emulate CC/PP passive discharge-identification and normal charging RC/R4/S3 conditions through `CC_PP_OUT`, while active CP waveform generation remains on a separate `CP_OUT` terminal. - Switch both line and neutral simultaneously using the two main poles of K1; do not swap L and N. - Keep PE permanently continuous from PE_IN to PE_OUT; PE is never software-switched. - Measure output current and voltage after the main relay for monitoring only. - Support Ethernet, isolated RS-485, SWD, UART debug, watchdog, and service jumper functions. ## Main Features - STM32G474RET6 MCU control core. - 24 V to 5 V conversion using LMR33630 and 5 V to 3.3 V using AP63203. - W5500 Ethernet and ADM2587E isolated RS-485. - Isolated ±15 V CP analogue supply using WRE2415S-1WR2. - MCP4922 DAC, REF5050 reference, 74AHCT125 logic buffer, OPA197 analogue stages, ADG1419 high-Z CP interruption. - HF170F/24-2H1DTF candidate main relay/contactor with auxiliary feedback. - 40 A / 20 mA CT current measurement and high-impedance L/N voltage measurement. ## System Architecture ```mermaid flowchart TD P24[External isolated 24 VDC] --> P5[LMR33630 5 V] P5 --> P33[AP63203 3.3 V] P33 --> MCU[STM32G474RET6] MCU --> ETH[W5500 Ethernet] MCU --> RS485[ADM2587E Isolated RS-485] MCU --> CPGEN[CP DAC / Buffer / OPA197 Stages] CPGEN --> CPSW[ADG1419 CP High-Z Switch] CPSW --> CPOUT[CP_OUT active CP terminal] MCU --> CCEMU[RC / R4 / S3 and Discharge Identification Network] CCEMU --> CCPP[CC_PP_OUT passive CC / PP terminal] MCU --> RELAY[Main Relay Coil Driver] RELAY --> ACMAIN[L/N Two-Pole K1 Switching] ACMAIN --> MEAS[Output Voltage and Current Measurement] MEAS --> MCU PEIN[PE_IN] --> PEOUT[PE_OUT Continuous] ``` ## Hardware Subsystems ### TOP_LEVEL_INTERFACES - Named sheet boundary nets and test points for 24V_IN, 5V, 3V3, +15V_ISO, -15V_ISO, **CP_OUT**, **CC_PP_OUT**, PE_IN/PE_OUT, L_IN, N_IN, L_OUT, N_OUT, RS485_A/B, Ethernet, SWD, UART, K1 control/feedback, ADC inputs, and service/watchdog signals. - Correct external vehicle-side terminals: `PE_OUT`, `CP_OUT`, and `CC_PP_OUT`. - `CC_PP_OUT` silkscreen text: **“CC / PP”**. - Do not use a separate `PP_OUT` terminal. ### POWER_MCU_COMMUNICATION - External isolated 24 VDC input. - 24V input protection placeholders: fuse, reverse-polarity protection, and TVS. Ratings/coordination are **REVIEW REQUIRED**. - STM32G474RET6 MCU. - LMR33630 24 V to 5 V buck; AP63203 5 V to 3.3 V buck. - W5500 Ethernet with generic RJ45 placeholder marked **VERIFY FOOTPRINT / PINOUT BEFORE RELEASE**. - ADM2587E isolated RS-485 with TVS and selectable 120 ohm termination. - SWD, UART debug, watchdog, and service jumper. ### CP_GENERATION_AND_MONITOR - 1 kHz CP signal. - Normal mode: +12 V / -12 V. - Test mode: independently programmable +11 V to +13 V and -11 V to -13 V platforms. - WRE2415S-1WR2 isolated ±15 V supply. - MCP4922 + REF5050 + 74AHCT125 + OPA197 + ADG1419. - 1.000 kOhm 0.1% CP series resistor. - Mandatory `R1_CP = 1.000kΩ`, 0.1%, 0.5W series resistor between the CP source switching circuit and `CP_OUT`. - `R1_CP` is the GB/T control-guide equivalent resistor R1; it is not optional and is not merely a protection resistor. - CP voltage monitor is connected on the `CP_OUT` side of `R1_CP`, relative to `PE_OUT`, and feeds the MCU/control domain through a review-required protection/isolation boundary. - Physical CP output disconnect/high-Z control is provided for test and engineering modes. - `CP_OUT` and `PE_OUT` test points are required. - In GB CP mode, the active CP waveform source may connect through the protected 1k output resistor to `CP_OUT`. - In EU/US PP mode, the active ±12 V CP generator must be physically disconnected/high impedance. - Never connect the CP waveform generator to `CC_PP_OUT`. - The PE-referenced CP analogue monitor domain and MCU/control domain require isolation/protection review. ### CC_PP_RC_R4_AND_DISCHARGE_IDENTIFICATION - External vehicle signal terminal for passive resistance identification: `CC_PP_OUT`, silkscreen **“CC / PP”**, plus `PE_OUT`. - No S2 detection/connection. - **Supersedes earlier terminal interpretation:** `PILOT_OUT` is obsolete. The schematic has been revised to use `CP_OUT` for active CP waveform generation and `CC_PP_OUT` for passive CC/PP resistance networks. - Normal charging RC/R4 path topology: `PE_OUT -> [selected R4 path OR S3 bypass switch across selected R4] -> selected RC -> RC enable switch -> CC_PP_OUT`. - R4 and RC are series elements in the normal charging route. - R4 selection and RC selection are independent; do not force value pairing. - S3 bypass switch is connected in parallel across the selected R4, so closing S3 bypasses R4. - The normal RC/R4 path is one complete selectable route. - RC values: 1.500k, 680R, 220R, with ±3% boundary test selections. - R4 values: 1.8k, 2.7k, 3.3k. - External-discharge identification paths are independent direct PE-to-`CC_PP_OUT` paths and do not pass through RC or R4: - `PE_OUT -> K_DIS_GB -> R_DIS_GB -> CC_PP_OUT`, with `R_DIS_GB = 2.00kΩ`, 0.5W axial flameproof. - `PE_OUT -> K_DIS_EU -> R_DIS_EU -> CC_PP_OUT`, with `R_DIS_EU = 50Ω`, 1W axial flameproof. - `PE_OUT -> K_DIS_US -> R_DIS_US (DNP) -> CC_PP_OUT`, vehicle-specific reserve with 1W axial-compatible through-hole footprint. - No universal US/J1772 discharge resistance is claimed. - Interlocking: the complete normal RC/R4 route must be mutually exclusive with every discharge-identification route. - Only one of K_DIS_GB, K_DIS_EU, and K_DIS_US may be active. - RC and R4 remain independently configurable within the normal charging route. - All passive resistance routes released must leave `CC_PP_OUT` open circuit. - `CC_PP_OUT` is used only as a passive resistance network for the vehicle to detect. The board does not measure CC/PP-to-PE voltage and must not include CC/PP voltage sensing. ### CHARGE_AND_DISCHARGE_CONTACTOR_CONTROL - Candidate: Hongfa HF170F/24-2H1DTF. - `K_CHG`: two-pole L/N charge contactor candidate HF170F/24-2H1DTF. - `K_DIS`: independent two-pole L/N discharge-output contactor placeholder. - `K_CHG` and `K_DIS` must never be closed simultaneously. - E_STOP_NC hardwired in series with the 24 V coil supply for both contactors. - >=100 V NMOS drivers, gate protection, flyback suppression, and optocoupler-isolated auxiliary feedback. - Relay pinout/footprint marked **VERIFY AGAINST SUPPLIER DRAWING OR SAMPLE**. ### AC_MAIN_PATH_AND_BIDIRECTIONAL_MEASUREMENT - Charge path: `L_IN/N_IN -> K_CHG -> L_VEH/N_VEH`. - Discharge path: `L_VEH/N_VEH -> K_DIS -> L_DIS_OUT/N_DIS_OUT`. - PE_IN, PE_OUT, and PE_DIS_OUT are permanently continuous; never switch PE. - CT placeholder on vehicle-side L conductor for bidirectional current polarity. - Vehicle-side L/N voltage measurement on `L_VEH/N_VEH` using symmetric high-impedance divider and differential AFE. - Report RMS voltage/current and signed real power direction in firmware/reporting. - Heavy 32A copper routing requirements are documentation only, not PCB layout. ### REVIEW_AND_TEST_STATE_TABLE - Captures normal charge, test, engineering, GB/EU/US discharge candidate modes, normal stop, emergency stop, relay interlock, all-open safe state, and unresolved safety/thermal/isolation/creepage/EMC/manufacturing review items. ## Power and Runtime Expectations - Powered from external isolated 24 VDC source. - On-board rails: 24V_IN, 5V, 3V3, +15V_ISO, -15V_ISO, 1V65_BIAS, REF_5V. - No battery/runtime requirement. ## Physical Design Expectations - PCB size target: 260 mm x 180 mm. - 4-layer, 2.0 mm FR-4, 4 oz outer copper. - 15 mm is the minimum continuous width target for the narrowest L/N heavy-copper path on the outer layers; it is not a thermal parameter. ## Important Design Decisions - Do not include RCD; rely on external upstream RCD/MCB. - Switch both L and N with K1; PE must remain permanently continuous. - Vehicle-side L/N may see reverse AC voltage up to normal input voltage for up to 30 seconds with relay open. - Use generic mechanical placeholders for HF170 relay, M6 AC terminals, RJ45, CT, and small relays. - Correct terminal ownership: `CP_OUT` is for active CP waveform generation and CP-to-PE monitoring only; `CC_PP_OUT` is for RC, R4/S3, and GB/EU/US passive discharge-identification resistors only. Never connect the CP generator to `CC_PP_OUT`, and never connect RC/R4/discharge resistors to `CP_OUT`. ## Review Required / Open Safety Checks - High-voltage safety and creepage/clearance. - Relay/contactor pinout, footprint, contact rating, auxiliary contact mapping, and coil behavior. - M6 terminal footprints and current/thermal rating. - Copper width, bottleneck, via stitching, and temperature rise at 32 A. - EMC, surge, ESD, transient, and protection strategy. - CT accuracy, voltage AFE safety, and measurement calibration. - Regulatory/safety compliance review by qualified personnel. ## Change Notes - Initial project specification created from user-provided requirements and corrected follow-up attachment. - Added CC/PP discharge-identification branch requirements and interlock constraints for GB, EU, and US/J1772 reserve branches. - Corrected terminal architecture again: `PILOT_OUT` is superseded. The board has three external vehicle-side terminals: `PE_OUT`, `CP_OUT`, and `CC_PP_OUT` with silkscreen “CC / PP”. No CC/PP-to-PE voltage sensing is required or allowed. - Clarified CP output resistor: `R1_CP` is mandatory GB/T control-guide equivalent R1, 1.000kΩ / 0.1% / 0.5W, and CP voltage monitoring is on the `CP_OUT` side of `R1_CP`. - Schematic revised to restore `CP_OUT` for active CP waveform generation/CP-to-PE monitoring and `CC_PP_OUT` for passive RC/R4/S3 and discharge-identification resistors, without PCB placement/routing/footprint work. - Full-board component-level schematic pass added the requested sheet groups, discharge-output terminals, K_DIS contactor path, 24V input protection placeholders, and bidirectional measurement documentation without PCB placement/routing/footprint work.