LTC3780 10A DC-DC Buck-Boost Converter - Automatic Step-Up/Down Power Module

Specifications

• Controller IC: Linear Technology LTC3780

• Module Architecture: Automatic Non-Isolated Buck-Boost (Step-Up/Step-Down)

• Input Voltage Range: 5.0V to 32V DC

• Output Voltage Range: 1.0V to 30V DC (Continuously Adjustable)

• Output Current: 10A Maximum (8A continuous recommended without forced air cooling)

• Output Power: 80W continuous, 130W peak (Requires active cooling above 80W)

• Conversion Efficiency: Up to 98% (Dependent on input/output differential)

• Switching Frequency: 200 KHz to 400 KHz

• Onboard Protection: Short-Circuit (Replaceable Fuse), Undervoltage Lockout (UVLO)

• Potentiometers: CV (Voltage), CC (Current), UV (Undervoltage)

• Dimensions: 77.6mm (L) x 46.5mm (W) x 15mm (H)

Key Applications and Projects

• Automotive PC Power Supplies: Conditioning the erratic 10V-15V power of a car battery into a perfectly clean, stable 12V output for delicate in-car entertainment systems.

• DIY Solar Charge Controllers: Taking fluctuating 18V-22V solar panel output and conditioning it with CC/CV limits to safely charge a 12V lead-acid battery bank.

• High-Power LED Drivers: Providing the exact voltage and strict current limiting required to power massive 50W and 100W Chip-On-Board (COB) LED arrays without thermal runaway.

Unlock New Capabilities (Project Evolution) The Universal Field Power Station: Do you fly RC drones or drive RC rovers? You often need 5V for receivers, 12V for battery chargers, and 24V for heavy tools out in the field. Build a universal power station! Wire the input of this LTC3780 to a cheap 18V drill battery adapter (like a Makita or DeWalt dock). Mount the board inside an ammo crate with a digital voltmeter screen and external knobs connected to the CV and CC pots. You have just created a portable, heavy-duty laboratory bench power supply that can deliver any voltage from 1V to 30V using your existing cordless tool batteries!

PACKAGE INCLUDED

• 1 x LTC3780 10A Buck-Boost Converter Module

FREQUENTLY ASKED QUESTIONS (FAQ)

1. What is a Buck-Boost converter? It is a power supply that can automatically step up (boost) or step down (buck) the input voltage to maintain your target output voltage. It bridges the gap when your input voltage fluctuates above and below your required output.

2. How is this different from a standard LM2596 module? The LM2596 is strictly a step-down (buck) converter and can only output a voltage lower than its input. The LTC3780 can output a voltage higher, lower, or exactly the same as its input.

3. What do the three blue potentiometers do?

• CV (Constant Voltage): Adjusts the output voltage up or down.

• CC (Constant Current): Sets the maximum allowable current limit to protect batteries or LEDs.

• UV (Undervoltage): Sets the minimum input voltage limit. If the input drops below this, the module shuts down to protect your input battery from dying completely.

4. How do I properly set the CC (Constant Current) limit? First, set the CV pot to your desired voltage without a load. Next, turn the CC pot fully counter-clockwise (lowest setting). Short the output terminals briefly with a multimeter set to the 10A Amperage range. Slowly turn the CC pot clockwise until the multimeter reads your exact desired current limit. Remove the short.

5. How do I set the UV (Undervoltage) protection? Provide your exact "cutoff" voltage to the input (e.g., dial a bench power supply to 10.5V). Connect a small load to the output. Turn the UV pot until the FAULT LED turns on and the output voltage drops to zero. Now, if your real battery ever hits 10.5V, the board will shut off.

6. What is the maximum wattage this board can handle? The board is generally rated for 80W of continuous power in still air. It can handle bursts up to 130W, but you MUST add a cooling fan blowing over the black heatsinks if operating above 80W for extended periods.

7. Does it have short-circuit protection? Yes. The CC limit will protect against basic overcurrent, and the board features a replaceable automotive-style blade fuse on the PCB for catastrophic short-circuit events.

8. Can I use this to charge lithium batteries? Yes. Because it features proper Constant Current (CC) and Constant Voltage (CV) controls, you can tune it to exact charging profiles (like 12.6V / 2A for a 3S LiPo pack).

9. Can I tie the input and output grounds together? Yes. This is a non-isolated converter. The IN- and OUT- terminals share a common electrical ground plane across the PCB.

10. What does the FAULT LED indicate? The red FAULT LED usually indicates that the input voltage has dropped below the threshold set by the UV potentiometer, or that a severe short-circuit has occurred.

11. Why does my output voltage drop when I connect my load? You are hitting your Constant Current (CC) limit. When a load tries to draw more current than you have allowed via the CC pot, the board intentionally drops the voltage to ensure the current stays at your exact limit.

12. Does it matter which way I turn the potentiometers? Generally, turning the small brass screw on the potentiometer clockwise increases the value (higher voltage/current), and turning it counter-clockwise decreases the value.

13. What is the input voltage range? It requires a minimum of 5V to power the logic chips and can accept up to a maximum of 32V DC.

14. What happens if I connect the input power backward? Do not do this! The standard version of this board does not have reverse-polarity protection on the input. Reversing the positive and negative input wires will instantly destroy the main control chip.

15. Can I use this with solar panels? Yes, it is excellent for taking the fluctuating 15V-22V output of a 50W/100W solar panel and stabilizing it to exactly 14.4V to charge a 12V battery array.

16. What kind of wire should I use for the terminals? If you are pushing the module to its 10A limit, you should use thick, high-quality 14AWG or 12AWG silicone wire. Thin jumper wires will melt under that load.

17. Can I put two of these modules in parallel to get 20 Amps? No. You should never wire switching regulators in parallel. Microscopic differences in their output voltages will cause one module to back-feed into the other, creating a feedback loop that will overheat and destroy both boards.

18. Why is there a switch or jumper pins labeled "ON/OFF"? The board usually breaks out a logic-level enable pin. You can wire a small toggle switch to this pin to turn the high-power output on and off remotely, without having to switch the massive 10A main power wire directly.

19. Are the black heatsinks electrically live? In many buck/boost designs, the metal tabs of the MOSFETs attached to the heatsinks can carry voltage. Do not let the heatsinks touch a metal enclosure, or you will cause a short circuit.

20. Will the board emit noise? The LTC3780 switches at high frequencies (up to 400KHz), which is completely silent to human ears. If you hear a high-pitched whining noise, your input power supply is likely too weak and the voltage is collapsing, causing sub-harmonic vibrations in the inductor.