Thought for 18 sec — Choosing components for low-power MCU
Found 3 results for Find Flux library USB input eFuse or protection switch IC for 5 V USB-C sink with adjustable/current limit around 0.75 to 1 A, overvoltage protection threshold above normal USB 5.25 V and below 9 V, undervoltage lockout, reverse current blocking, soft-start/inrush control, active SMD part. Prefer TI TPS2595 TPS2596 TPS2594 AP2265 AP22802 style eFuse..
Crea una placa basada en esp32 wroom la cual este adaptada para trabajar con una bateria 18650 y un panel solar, ademas a esta placa agrega 2 relays para usarlos como auxiliares, concidera ademas un socket para poner un modulo lora ebyte e220. para los sensores deja un modulo MAx asi conectar sensores rs485 y sensores industriales. diseño compacto}
No pude modificar el proyecto porque no hay ACUs disponibles.
Estado actual:
El proyecto sigue vacío: 0 componentes y 0 redes.
Queda por diseñar la arquitectura con ESP32-WROOM, batería 18650, entrada para panel solar con cargador/power-path, 2 relés auxiliares, socket para Ebyte E220 LoRa, interfaz RS-485 industrial con protección y conectores de sensores.
También faltan selección de componentes, esquema, verificación ERC y diseño PCB compacto.
Antes de ejecutar conviene definir el voltaje/potencia del panel solar, la tensión/corriente de las cargas de los relés y el modelo exacto del E220, porque determinan el cargador, protecciones, contactos y pinout del socket.
A consumer USB-C powered temperature and relative humidity sensor node with Wi-Fi and Bluetooth Low Energy connectivity. The board uses a protected USB-C 5 V sink input, local 3.3 V regulation, a low-power Wi-Fi/BLE MCU module, and a digital I2C T/RH sensor.
Intended Use
Indoor consumer environmental monitoring node.
Powered from USB-C 5 V chargers, hubs, or ports.
Designed for prototype-to-production learning; not medical, industrial safety, or outdoor/weatherproof use unless later specified.
What the Device Should Do
Measure ambient temperature and relative humidity.
Connect over 2.4 GHz 802.11 b/g/n Wi-Fi.
Support BLE 5.x provisioning or local telemetry.
Power from USB-C default 5 V sources.
Survive common consumer input faults with reverse-current, overvoltage, undervoltage, and overcurrent protection.
Main Features
USB-C receptacle configured as sink-only with independent CC1/CC2 5.1 kΩ Rd resistors.
Protected 5 V input sized for 0.5–3 A capable sources, while the node itself is expected to draw well below 500 mA average.
3.3 V logic rail for MCU and sensor.
Native USB data/programming path where supported by the selected MCU.
Boot/reset controls, debug/programming access, and status LED.
System Architecture
Diagram
Hardware Subsystems
Power input: USB-C receptacle, CC pull-downs, VBUS ESD/TVS, protected power switch/eFuse or load switch with OVP/UVLO/OCP/reverse-current blocking.
Regulation: 5 V to 3.3 V rail sized for Wi-Fi transmit current peaks.
Compute/radio: certified ESP32-family module preferred to avoid custom RF matching and simplify regulatory work.
Sensor: digital I2C temperature/humidity sensor with local decoupling and one shared I2C pull-up pair.
User/debug: reset and boot controls, status LED, USB programming, optional exposed test/debug header.
Interfaces and Connections
External: USB-C 5 V power and USB 2.0 D+/D- for programming/debug.
Internal: 3.3 V rail, GND, I2C SDA/SCL, boot/reset, status LED GPIO.
RF: integrated 2.4 GHz antenna module; PCB layout must provide the module antenna keepout.
Power and Runtime Expectations
Source: USB-C 5 V default power only; no battery in this revision.
Source capability planning: tolerate 0.5 A, 1.5 A, and 3 A capable USB-C sources. Do not assume the device may draw 3 A unless CC current advertisement is measured/implemented.
Low-power behavior: firmware should sleep between samples and radio transmissions, but USB-powered operation makes absolute sleep current less critical than thermal and regulatory behavior.
Power Tree and Power Budget
Table
Rail
Load
Sleep
Typical active
Peak
3.3 V
Wi-Fi/BLE MCU module
~10–100 µA deep sleep
~80–240 mA radio active
~500 mA short Wi-Fi TX burst
3.3 V
T/RH sensor
<1 µA standby
~0.5–1 mA measuring
~1 mA
3.3 V
Status LED
0 mA off
~2 mA on
~5 mA configured max
3.3 V
Pull-ups/leakage
~1–2 mA worst when lines low
negligible average
~1.4 mA for two 4.7 kΩ pull-ups low
Estimated 3.3 V rail sizing target: 250 mA typical active, 510 mA transient peak. For an LDO from 5 V, input current is approximately output current; thermal at 250 mA is about (5.25 V - 3.3 V) × 0.25 A = 0.49 W, so a small SOT-23 LDO may be marginal during sustained Wi-Fi. Preferred choices are a high-current low-Iq regulator in a thermally capable package or a quiet buck regulator if sustained radio current/thermal limits demand it.