VNX-SCCB – Smart Pre-Charge & Battery Charging Controller
A single-board power controller built for mobile robot platforms — controlled inrush start-up, monitored XT30 battery charging, and multi-protocol status reporting in one 22–60 V design.
| 22–60 V Battery input / output | 12 A Continuous charge current | −40…125°C Operating range | CAN · SPI · UART · I²C Onboard protocols |
Overview
The VNX-SCCB combines a high-side pre-charge / reverse-polarity protection stage with a monitored battery charging front-end on a single compact PCB. It is designed for the two moments in a mobile robot’s power cycle that cause the most field failures: the instant a battery is connected or a robot docks, and the period while it charges unattended.
On the input side, a high-side N-channel MOSFET controller with back-to-back MOSFET support brings the bus up in a controlled, current-limited ramp — protecting connectors, capacitor banks, and downstream electronics from inrush transients and reverse-polarity connection. On the charging side, an XT30-terminated stage delivers up to 12 A of monitored current with soft-start behavior that remains stable even at very low starting battery voltage, and shuts off automatically once the configured charge voltage is reached.
A central MCU exposes system status over CAN, SPI, UART and I²C, so the board can report voltage, current, temperature, and fault state to a host controller, dock, or fleet-management system in real time. The result is a drop-in power stage for AMR and AGV platforms, automatic docking stations, and other unattended industrial power systems.
| AT A GLANCE | |
| Battery chemistries | Li-ion / LiFePO₄ |
| Nominal systems | 24V / 33V / 48V class |
| Wide input / output | 22–60 V DC |
| Charge connector | XT30 |
| Comms | CAN / SPI / UART / I²C |
| Status LEDs | HB · CHG · FULL · ERR · PG |
Key Features
| Full protection suite Reverse-polarity, reverse-current, over-voltage, UVLO, ESD and inrush current control on a single power stage. | High-side MOSFET pre-charge N-channel high-side controller with back-to-back MOSFET support, fast turn-on / turn-off, and enable control input. | 12 A monitored charging XT30 charge input with real-time V/I monitoring, 1 A soft-start at low battery voltage, and automatic cutoff at full charge. |
| Multi-protocol comms Dedicated CAN bus, SPI (with NFC-module support), TTL UART, and I²C headers for flexible robot-system integration. | External NTC sensing Dedicated NTC input for battery-pack temperature measurement feeding into charge control and fault reporting. | PWM fan output Onboard fan header for active thermal management of the MOSFET banks under sustained charge current. |
| Live status LEDs HB (heartbeat), CHG, FULL, ERR and PG indicators give a field-visible read of system state without a host connection. | −40°C to 125°C operation Industrial-grade component selection for outdoor docks, cold storage AGVs, and continuous-duty warehouse robots. | Compact embedded form factor Dual XT30 pigtails and edge-mounted headers keep the board footprint low for tight chassis integration. |
Interface Map
Annotated top-view of the VNX-SCCB prototype, showing the charging path, communication headers and monitoring points referenced throughout this document.
Legend
- XT30 charge / output — 22–60 V battery
- UART / SPI — TTL UART (RX/TX/GND) and SPI (SCK/MISO/MOSI/CE/5V/GND/IRQ/RST) for local peripherals and NFC modules.
- CAN ×2 — Dual CAN connectors for system control, battery monitoring, and fault reporting on the robot bus.
- NTC / I²C — External NTC input plus 5V-GND-SDA-SCL header for auxiliary sensors.
- Status & test — HB / CHG / FULL / ERR / PG LEDs
| SPI communication interface – Dedicated SPI interface, suitable for connecting NFC modules – Supports various SPI-based sensors and peripheral devices – High-speed communication for local peripherals – Designed for flexible robot-system integration | CAN bus & battery monitoring – CAN bus communication for system-level control – Enables battery input / output monitoring – Supports battery voltage and current monitoring – System status and fault monitoring for BMS / power management / safety systems |
| TTL UART interface – Local debug and configuration access – Pairs with the external NTC input for temperature read-back – Low pin-count connection for host bring-up | XT30 charging & protection – Up to 12 A continuous charging current – 1 A soft-start charging, stable even at very low battery voltage – Automatic cutoff at the configured charge voltage, slow / fast charging modes |
Specifications
Power input / output
| Parameter | Condition | Value |
| Battery voltage range | Li-ion / LiFePO₄ | 22–60 V DC |
| Target system classes | Nominal pack voltage | 24 V / 33 V/ 48 V |
| Charge connector | — | XT30 |
| Continuous charge current | — | up to 12 A |
| Soft-start current | Low battery voltage | 1 A |
Protection & safety
| Parameter | Notes | Value |
| Reverse-polarity protection | Input & charge path | Yes |
| Reverse-current protection | — | Yes |
| Over-voltage protection | — | Yes |
| Under-voltage lockout (UVLO) | — | Yes |
| Inrush current control | High-side MOSFET start-up | Yes |
| ESD protection | — | Yes |
| MOSFET topology | Pre-charge / power path | High-side N-ch, back-to-back |
Control & communication
| Parameter | Notes | Value |
| CAN bus | ×2 connectors DAISY Ccon. | Yes |
| SPI | NFC / sensor peripherals | Yes |
| TTL UART | RX / TX / GND | Yes |
| I²C | 5V-GND-SDA-SCL header | Yes |
| Temperature sensing | External NTC input | Yes |
| Enable / ON-OFF control | PRE CHARGE AND MAX CHARGE | Yes |
| Status indicators | — | HB · CHG · FULL · ERR · PG |
Environmental
| Parameter | Notes | Value |
| Power consumption | Standby / idle | Low (design-dependent) |
| Cooling | MOSFET bank | Onboard PWM fan header |
Applications
Any platform that connects to a battery unattended, or charges without a person watching, benefits from a monitored pre-charge and charging stage.
| AMR & AGV platforms Onboard pre-charge protection and charge monitoring for autonomous mobile robots and automated guided vehicles. | Automatic docking & charge stations Controlled contact-plate or connector engagement with soft-start current limiting and reverse-polarity protection. |
| Industrial power distribution High-side switched power branches with UVLO and OVP for machine-level power sequencing. | Warehouse & logistics robots Continuous-duty rated protection stage for fleets running multi-shift charge cycles with minimal supervision. |
| Battery management front-ends CAN / I²C-reported voltage, current and temperature data for integration into a larger BMS or fleet system. | Outdoor & cold-chain equipment −40°C to +125°C rated design intent for AGVs and equipment operating in unheated or refrigerated spaces. |
Mechanical & Form Factor
Board outline, mounting-hole pattern and connector stack-up shown on the current revision.
| Board length | 110 mm |
| Board width | 65 mm |
| Board thickness | 25 mm |
| Mounting hole diameter | 3 mm |