XL4015 5A Li-ion battery charging/LED drive/buck constant current power module

SKU: FA2102-2
Input Voltage Range

DC 5V – 36V (max 40V absolute)
Output Voltage Range

DC 1.25V – 32V (adjustable)
Output Current Range

0 – 5A (adjustable current limit)
Output Power (Max)

75W (with adequate cooling)
Conversion Efficiency

Up to 96%
Switching Frequency

180 KHz (fixed)
Output Ripple

< 50mV (typical)
Short Circuit Current Limit

8A (typ.)
Operating Temperature

-40°C to +85°C

Description

The XL4015 5A CC-CV Step-Down Power Module is a versatile, high-performance DC-DC buck converter designed for applications requiring precise constant current (CC) and constant voltage (CV) regulation. Whether you need to charge lithium-ion batteries, drive high-power LEDs, or create a benchtop power supply with adjustable current limiting, this module delivers reliable, efficient performance.

At the heart of this module is the XL4015 chip from XLSEMI – a 180KHz fixed frequency PWM buck converter that integrates a high-current 5A power MOSFET . Unlike standard voltage-only regulators, this module features dedicated CC-CV control circuitry, allowing you to independently set both the output voltage and the maximum output current .

CC-CV (Constant Current – Constant Voltage) Explained:

This module operates in two distinct modes, automatically switching between them based on load conditions :

Mode Description When Active
Constant Current (CC) Output current is held at the user-set limit; voltage drops as needed When load tries to draw more than the set current (e.g., charging a deeply discharged battery)
Constant Voltage (CV) Output voltage is held at the user-set value; current varies with load When load draws less than the set current limit (e.g., battery near full charge)

Key Applications :

  • Lithium Battery Charger: Set the float voltage (e.g., 4.2V for single Li-Ion cells) and charging current – the module automatically switches from CC to CV when the battery reaches full charge. An onboard LED indicates charging status .

  • LED Constant Current Driver: Drive high-power LEDs at their specified current (e.g., 3A, 5A) without needing additional resistors. The module maintains a constant current regardless of LED forward voltage variations.

  • Adjustable Bench Power Supply: With built-in current limiting, this module can power sensitive circuits safely – if your prototype shorts, the current limit prevents damage.

Comprehensive Protection Features :

  • Built-in thermal shutdown – Automatically shuts down when overheated

  • Current limiting – User-adjustable from 0-5A via onboard potentiometer

  • Output short protection – Reduces switching frequency from 180KHz to 48KHz during shorts

  • Charge status indicator – LEDs show charging in progress and battery full

Important Operating Note: This module is a step-down (buck) converter only. The input voltage must always be at least 1.5V higher than the desired output voltage. It cannot step up voltage .

Whether you are building a custom battery charger, designing an LED lighting system, or creating a safe benchtop power supply, the XL4015 CC-CV module provides the precision current limiting and voltage regulation you need.

Key Features

  • CC-CV (Constant Current – Constant Voltage) Control – Independently adjustable current limit (0-5A) and output voltage (1.25-32V) for battery charging and LED driving

  • 5A Maximum Output Current – Integrated 5A power MOSFET delivers up to 5A (4A-4.5A recommended continuous with heatsink)

  • Wide Input Voltage Range – Accepts DC 5V to 36V input, compatible with 12V, 24V, and 36V power systems

  • Adjustable Output Voltage – Output can be set from 1.25V to 32V via onboard multi-turn potentiometer

  • High Conversion Efficiency – Up to 96% efficiency minimizes power loss and heat generation

  • 75W Maximum Output Power – Capable of delivering up to 75W output power (with adequate cooling)

  • Dual LED Indicators – Shows module status: power on, constant current mode active, battery charging, and battery full

  • Comprehensive Protection – Built-in thermal shutdown, over-current limiting, and output short protection

  • Low Output Ripple – <50mV typical ripple provides clean DC output for sensitive electronics

  • Wide Operating Temperature – -40°C to +85°C for reliable operation in various environments

Technical Parameters

Parameter Value
Input Voltage Range DC 5V – 36V (max 40V absolute)
Output Voltage Range DC 1.25V – 32V (adjustable)
Output Current Range 0 – 5A (adjustable current limit)
Output Power (Max) 75W (with adequate cooling)
Conversion Efficiency Up to 96%
Switching Frequency 180 KHz (fixed)
Output Ripple < 50mV (typical)
Short Circuit Current Limit 8A (typ.)
Operating Temperature -40°C to +85°C

Usage Guide

How CC-CV Works

This module automatically switches between two regulation modes :

  1. Constant Current (CC) Mode: When the load tries to draw more current than the user-set limit, the module reduces the output voltage to maintain the current at the set value. The CC indicator LED lights up .

  2. Constant Voltage (CV) Mode: When the load draws less than the set current limit, the module maintains the output voltage at the user-set value. This is the normal operating mode for most loads.

Example – Charging a 3.7V Li-Ion Battery (2200mAh): 

  • Float voltage = 4.2V

  • Charging current = 2200mA (1C)

  • Module starts in CC mode (constant 2200mA, voltage rises as battery charges)

  • When battery reaches 4.2V, module switches to CV mode (constant 4.2V, current gradually decreases)

  • When current drops to 10% of set value, “full” LED indicates charge complete

Pinout Description

Terminal Label Function
IN+ Input Positive (+) Connect to your DC power source positive terminal (5V-36V)
IN- Input Negative (-) Connect to your DC power source negative terminal (ground)
OUT+ Output Positive (+) Connect to battery positive or load positive
OUT- Output Negative (-) Connect to battery negative or load negative

Wiring Instructions

Step 1 – Connect Input Power

  • Connect the positive (+) wire of your DC power source to IN+

  • Connect the negative (-) wire to IN-

  • Input voltage must be at least 1.5V higher than desired output voltage

Step 2 – Connect Load

  • For battery charging: Connect battery positive to OUT+, negative to OUT-

  • For LED driving: Connect LED anode to OUT+, cathode to OUT-

Setting the Output Voltage (No Load)

  1. Power on the module with no load connected to the output

  2. Use a digital multimeter to measure voltage between OUT+ and OUT-

  3. Turn the “Voltage” potentiometer (typically blue) to adjust:

    • Turn clockwise to increase voltage

    • Turn counter-clockwise to decrease voltage

  4. Set to desired voltage (e.g., 4.2V for single Li-Ion, 12.6V for 3S LiPo)

Setting the Output Current Limit

⚠️ IMPORTANT: This step must be done with the output shorted 

  1. Short the output terminals – Connect OUT+ directly to OUT- with a wire

  2. Set your multimeter to measure current (10A range) in series with the short

  3. Turn the “Current” potentiometer to adjust the current limit:

    • Turn clockwise to increase current limit

    • Turn counter-clockwise to decrease current limit

  4. Set to desired current (e.g., 1A for 1000mAh battery)

  5. Remove the short – the module is now configured

LED Indicators

LED Color Meaning
CC Indicator Blue/Red Module is in Constant Current mode (current limiting active)
Charging LED Red Battery charging in progress
Full LED Green Battery fully charged / module in CV mode

Critical Adjustment Note – Multi-Turn Potentiometers

This is the most important point for new users. The module uses multi-turn potentiometers (typically 25-30 turns from end to end) .

If the output voltage is not changing when you turn the screw:

  • You have likely reached the end of the adjustment range and need to turn in the opposite direction

  • Try turning the screw counter-clockwise many turns (10-15 full rotations) until the voltage starts to decrease

  • If voltage remains at input voltage, the potentiometer is at its maximum – keep turning counter-clockwise

Many modules ship with the voltage preset to approximately 20V – do not be alarmed if your initial reading is high .

Charging Lithium Batteries – Step by Step

  1. Determine battery parameters: For a single 18650 (3.7V, 2200mAh):

    • Float voltage = 4.2V

    • Max charging current = 2200mA (1C)

  2. Set voltage (no load): Adjust “Voltage” potentiometer to 4.2V

  3. Set current (output shorted): Short output, adjust “Current” potentiometer to 2.2A

  4. Remove short and connect battery

  5. Monitor charging:

    • Red LED ON = charging (CC mode)

    • Green LED ON = full (CV mode, current has dropped)

Driving High-Power LEDs – Step by Step

  1. Determine LED specifications: e.g., 10W LED requires 3.3V @ 3A

  2. Set voltage (no load): Adjust “Voltage” potentiometer to 3.3V

  3. Set current (output shorted): Short output, adjust “Current” potentiometer to 3A

  4. Remove short and connect LED

  5. The module will regulate constant current – voltage will adjust automatically to maintain 3A

Important Operating Restrictions

Voltage Limitation (Critical):
This module is a step-down (buck) converter only. The input voltage must always be at least 1.5V higher than the output voltage. If input drops below output, the module cannot regulate and output will follow input .

Reverse Polarity Warning:
This module does NOT have reverse polarity protection. Double-check connections before applying power. If reverse protection is needed, add a high-current diode in series with the input .

Current Limit Behavior:
When the current limit is active (CC mode), the CC indicator LED will light . This is normal during battery charging or when powering loads that exceed your set limit.

Example Applications

Application Input Source Output Setting Current Setting
Single Li-Ion Battery Charger 12V power supply 4.2V Battery capacity (C)
3S LiPo Battery Charger 24V power supply 12.6V Battery capacity (C)
10W LED Driver 12V battery 3.3V 3A
Benchtop Power Supply 24V adapter 1.25-20V adjustable As needed for circuit protection

Installation Tips

  • Polarity Check: Always double-check input polarity before applying power

  • Initial Setup: Set voltage and current with no load before connecting batteries

  • Heatsink: For loads above 2.5A continuous, attach a heatsink to the XL4015 chip

  • Short Protection: The module includes short protection, but avoid prolonged shorts

  • Keep Wires Short: Long wires add resistance and voltage drop, affecting current limit accuracy

Q: What is the difference between this module and a standard voltage regulator?

A standard voltage regulator maintains a fixed voltage regardless of current. This CC-CV module allows you to set both the voltage AND the maximum current. When the load tries to draw more than the set current, the module automatically reduces voltage to keep current at the limit . This is essential for battery charging and LED driving.

Q: Why do I need to short the output to set the current?

Shorting the output forces the module into Constant Current (CC) mode, allowing you to set the current limit accurately. This is the correct procedure for all CC-CV modules

Q: Why is my output voltage not changing when I turn the potentiometer?

The module uses a multi-turn potentiometer (25-30 full turns from end to end) . If you reach the end of its range, turning further has no effect. Try turning the screw counter-clockwise many turns until the voltage starts to decrease. The module may ship with output preset to approximately 20V

Q: What is the maximum continuous current I can draw?

With proper cooling:

  • Up to 2.5A: Safe without heatsink

  • 3A – 4A: Requires heatsink and adequate airflow

  • 4A – 4.5A: Requires good heatsink and cooling

  • 5A: Peak/short duration only (chip’s switch current limit)

Q: Can I use this module to charge any lithium battery?

Yes, for any lithium battery (Li-Ion, LiPo, LiFePO4) within the voltage and current range. You must:

  • Set the correct float voltage for your battery type

  • Set the charging current to ≤ battery’s rated C rating

  • For multi-cell batteries, ensure you have proper balancing – this module charges series packs directly, but parallel packs are safer without a BMS

Battery Type Float Voltage (per cell)
Li-Ion / LiPo 4.2V
LiFePO4 3.6V
Q: Why is my CC indicator LED lit during battery charging?

This is normal. When charging a deeply discharged battery, the module operates in Constant Current (CC) mode, delivering the set current while the battery voltage rises. When the battery approaches the float voltage, the module switches to Constant Voltage (CV) mode and the CC indicator turns off

Q: Can I use this module as a benchtop power supply?

Yes. The adjustable current limit makes this an excellent benchtop supply for prototyping. Set the voltage to your desired level, then set the current limit to a safe value (e.g., 100mA for sensitive circuits). If you accidentally short your circuit, the module will limit current rather than letting damaging current flow.

Q: Does this module have reverse polarity protection?

No. This module does not have reverse polarity protection. Connecting input backwards will instantly destroy the module. If reverse protection is needed, add a high-current diode in series with the input positive line

Q: What is included in the package?

  • 1 x XL4015 5A CC-CV Step-Down Module

  • (Heatsink may not be included – check product listing)

Q: Why is my module getting very hot?

Heat is normal in any high-power DC-DC converter, especially when:

  • Operating in CC mode at high current (e.g., charging a deeply discharged battery)

  • Drawing >2.5A continuous

  • Input-output voltage difference is large

  • Operating without adequate airflow

Solutions: Add a heatsink, reduce current, improve airflow, or use a higher input voltage to reduce conversion ratio.

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