Hardware Overview¶
Architecture¶
The regulator is built around an ESP32-S3 microcontroller. Hardware was all selected for ultra-low power consumption, wide voltage ranges, and robust protection for harsh environments.
Some Hardware Specifications¶
| Parameter | Specification | Notes |
|---|---|---|
| Input Voltage | 4.2V - 65V | Via TPS4800-Q1 protection |
| Typical Operating Voltage | 12V/24V/48V | Marine/automotive systems |
| Operating Temperature | -40°C to +85°C | Industrial grade components |
| Field Current Control | Up to 15A | PWM controlled |
| Alternator Current Measurement | ±200A capability | Via external Hall-effect clamp-on meter |
Power System¶
Multi-Stage Power Architecture¶
Battery (4.2-65V) → TPS4800-Q1 → LMR36510 (5V) → TLV62569 (3.3V) → ESP32-S3
Key Features: - Primary Protection: TPS4800-Q1 high-side driver with overcurrent, overvoltage, and reverse polarity protection - Dual Buck Converters: High-efficiency switching supplies (87-94% overall efficiency) - USB-C Alternative: Programming and development power via USB-C with jumper selection - Power Isolation: Complete battery disconnect via jumper control for USB operation
Processing Core¶
ESP32-S3 Controller¶
- Architecture: Dual-core Xtensa LX7 @ 240MHz
- Memory: 16MB Flash, 8MB PSRAM
- Connectivity: WiFi 802.11b/g/n, native USB OTG
- I/O Capabilities: Sufficient GPIO for all analog inputs, digital I/O, communications
- Programming: USB-C native programming (no USB-to-serial converter required)
Selection Rationale: - Native USB support eliminates external converters - Ample GPIO and processing power for real-time control - Integrated WiFi for remote monitoring and configuration - Low-power sleep modes for battery applications
Input/Output Systems¶
Analog Inputs (ADS1115 + TLV9154)¶
4-channel precision measurement system with op-amp buffering:
| Channel | Function | Range | Resolution | Power Consumption |
|---|---|---|---|---|
| 0 | Battery Voltage | 0.21V - 65.2V | 2.1mV | 22.5µA @ 12V input |
| 1 | Alternator Current | ±200A (via hall sensor) | 0.02A theoretical | 10.8µA |
| 2 | Engine RPM | 8Hz - 2640Hz | Variable by setup | 10.8µA |
| 3 | Temperature | 15°C - 125°C* | 0.8-5.8°C | 115µA @ 25°C |
*Limited by 5V supply configuration - see documentation for details
Design Features: - High-impedance voltage dividers minimize power consumption - Unity-gain op-amp buffers prevent loading errors - Single 3.3V supply with inherent overvoltage protection - 16-bit ADC resolution with 0.1mV LSB sensitivity
Digital Inputs¶
Two architectures for different applications:
Optocoupler Style (6 channels): - Activation input range: 5V - 54V - Power consumption: 0.16mA - 33.7mA @ 12V equivalent (when active) - Applications: Any on/off voltage signals
Ground Style (4 channels): - Activation: Short to ground - Continuous power: 0.09mA @ 12V equivalent - RC debounce filtering with ESD protection - Applications: Switch inputs, mode selections
Digital Outputs¶
Buzzer/Relay Control: - High-side P-channel MOSFET switching - 5V supply, up to 500mA recommended - Flyback protection for inductive loads - 0.35mA idle current @ 12V equivalent
Communication Interfaces¶
UART Isolation (2 channels): - HCPL2531 optocoupler isolation (2500V) - NMEA0183 and VE.Direct compatible - 1.86mA @ 12V equivalent power consumption - Up to 1MBaud data rates
NMEA2000 CAN: - Isolated CAN transceiver (ISO1050DUB) - 12V boat power to isolated 5V conversion - Selectable 120Ω termination - 20-25mA standby current from 12V boat supply
Pressure/Temperature Sensor: - BMP390 barometric p/t sensor - I2C interface, 3.3V supply
Field Control System¶
Alternator Field Driver¶
High-current PWM control system:
Architecture:
5V → MT3608 Boost (12V) → LM5109A Driver → MOSFET (~15A max)
Specifications: - Field current: Up to 15A continuous - PWM frequency: 100Hz - 20kHz+ - Flyback protection for inductive field loads - Bootstrap driver for high-side switching
Current Limitations: - MT3608 boost limited by BAT54J diode (200mA continuous) - Thermal management required for high-frequency operation - Parallel MOSFETs may be unnecessary , planning to remove 1 in test
Battery Monitoring¶
INA228 Current/Voltage Monitor¶
High-precision battery state monitoring:
Configuration: - Bus voltage: Direct battery measurement (up to 85V rating) - Current: Low-side shunt measurement (±163.84mV differential range) - Interface: I2C at address 0x40 - Resolution: 16-bit with programmable gain
Protection: - P6SMB68A TVS protection (58.1V standoff for 48V systems) - RC filtering on all inputs (1.59kHz cutoff) - ESD protection diodes on differential inputs
Power Consumption: - Normal operation: 3.63mW (1.1mA @ 3.3V) - Shutdown mode: 9.24µW (2.8µA)
Tachometer Output¶
Signal conditioning for dashboard tachometer:
- Input: ESP32 frequency signal (8Hz - 2.64kHz)
- Output: Battery voltage level square wave
- Drive capability: Standard automotive tachometers
- Power: 0.54mA - 13.6mA @ 12V (depending on supply voltage and duty cycle)
Protection Systems¶
Input Protection (TPS4800-Q1)¶
Comprehensive automotive-grade protection:
Protection Features: - Reverse polarity: -65V maximum - Overvoltage: 58.8V - 61.5V shutdown threshold - Overcurrent: 15.1A with 3µs response time - Undervoltage lockout: 6.8V turn-on threshold - Auto-retry: 5-second intervals after fault
Power Management: - 43µA quiescent current when enabled - Complete power path isolation via jumper control - Hierarchical TVS protection for severe transients
ESD and Transient Protection¶
Multi-layer protection throughout system:
- TVS diodes on power inputs and high-voltage signals
- ESD protection on all exposed I/O
- RC filtering before sensitive analog inputs
- Bidirectional TVS arrays on communication lines
PCB Considerations¶
Design Requirements¶
- 4-layer PCB recommended for thermal management and noise reduction
- Wide traces for high-current paths (field driver, power supplies)
- Proper ground plane separation for isolated circuits
- Thermal vias for power-dissipating components
- Marine-grade conformal coating compatibility
Component Selection¶
- Industrial temperature range (-40°C to +85°C)
- High-reliability automotive-grade components where applicable
- Standard values (1% resistors, common capacitor values) for easy sourcing
- AEC-Q200 qualified components for critical protection circuits
Development and Programming¶
USB-C Interface¶
Native programming and debugging:
- ESP32-S3 native USB OTG (no USB-to-serial converter)
- Power delivery capability with jumper control
- ESD protection on data lines
- Manual boot control (GPIO0 + reset) for programming
Power Source Management¶
Jumper-controlled power source selection:
| Battery Jumper | USB Jumper | Result | Use Case |
|---|---|---|---|
| Installed | Removed | Battery only | Production operation |
| Removed | Installed | USB only | Development/programming |
| Removed | Removed | No power | Safe configuration |
System Integration¶
Typical Application Connections¶
- Battery positive/negative for monitoring and power
- External shunt resistor for current measurement (75-150µΩ, 500A rating)
- Alternator field winding connection
- Alternator current sensor (included hall effect clamp)
- Engine RPM signal (alternator stator or other frequency source)
- Temperature sensor (10kΩ NTC thermistor or Digital sensor (included))
- Digital inputs for engine/system status
- NMEA2000 connection for marine network integration
- VeDirect and/or NMEA0183 as needed
Performance Summary¶
- Ultra-low quiescent current suitable for continuous battery monitoring
- High-efficiency power conversion minimizes heat generation
- Robust protection systems handle marine electrical environment
- Comprehensive I/O capabilities for complete engine/charging system monitoring
This hardware platform provides a complete solution for intelligent alternator regulation and battery management in marine and automotive applications, with emphasis on reliability, efficiency, and comprehensive monitoring capabilities.