01 Overview

Ultra-mini boost module built around the SX1308 step-up converter, a high-efficiency, low-quiescent-current synchronous boost IC.

Input voltage range typically 2V–24V, output adjustable up to 28V, suitable for powering from a single-cell Li-ion battery or USB 5V.

Small footprint, ideal as an auxiliary supply in ESP32 or other low-power embedded systems, e.g., to provide a higher voltage rail for sensors, displays, or motor drivers.

It solves the problem of generating a stable higher voltage rail when the main supply is insufficient, without adding significant size or cost.

It is not an isolated supply; input and output share ground. It is also not a high-precision LDO; output ripple and transient response must be evaluated against the load.

Typical applications include portable instruments, battery-powered IoT nodes, and DIY electronics where a boost supply is needed.

02 Hardware

Core: SX1308 boost converter with integrated switch; no external MOSFET required.

Input: VIN (typical 2V–24V), GND. Note that input voltage must be lower than output voltage for boosting to occur.

Output: VOUT (adjustable, up to 28V), GND. Output voltage is set by the feedback resistor network; a default value is pre-configured on the board (see schematic).

Enable pin: EN (high to enable, low to shut down). It has an internal pull-up, so it is enabled by default when floating.

Feedback resistor network sets the output voltage; users can change resistors to adjust output, but must respect the feedback reference voltage (see schematic).

Inductor and input/output capacitors are integrated; only input and output connections are required.

Layout notes: keep input/output capacitors close to the chip pins, and inductor traces short and wide to reduce parasitics and EMI.

Thermal: at high output currents the chip will heat; ensure sufficient copper area for heat dissipation.

03 Software flow

This is a pure hardware boost circuit; no firmware or software flow.

For ESP32 projects, first confirm that the output voltage and load current are within module specifications.

Connect the module output to the ESP32's 5V or 3.3V rail (ensure voltage compatibility to avoid overvoltage damage).

To control power on/off, connect the EN pin to an ESP32 GPIO and drive it high/low to enable/disable the module.

In ESP32 firmware, configure the GPIO as push-pull output, initialize it low to disable output, and set high when needed.

Add a bulk capacitor (e.g., 100uF electrolytic) at the output to reduce ripple, especially during load transients.

If the output feeds analog circuits, consider adding an LC filter or a low-noise LDO for secondary regulation.

Note: the ESP32's ADC can monitor the output voltage, but a voltage divider is needed to scale it down to 0-3.3V.

04 Core points

No MCU core; purely analog power module, not programmable.

Output voltage is set by hardware resistors; changing output requires resistor replacement, not software adjustment.

Input voltage must be lower than output voltage; otherwise the module cannot operate correctly.

Maximum output current is limited by input voltage, output voltage, and inductor selection; current capability decreases with higher boost ratios.

The EN pin should not be left floating in noisy environments; drive it explicitly to avoid false triggering.

No reverse polarity protection is built into the SX1308; external protection is required.