Project description

1. The design index of this desktop mobile power bank is:

Input: 48Vmax

Output: 12V 58.4A 0.2Vpp

Operating frequency: 200kHz

2. Synchronous freewheeling scheme: LM5143 is a 65V synchronous buck DC/DC controller suitable for high current single or dual output.

Open source license

CC-BY-NC-SA 3.0, Creative Commons Licensing Agreement - Attribution - Non-Commercial Use - Share Like-Like

CC : Abbreviation for Creative Commons Licensing Agreement (English: Creative Commons license )

BY : Attribution, you must give appropriate attribution, provide a link to this Licensing Agreement, and indicate whether modifications have been made (to the original work).

SA: If you remix, transform, or build upon this work, you must share your contribution under the same Licensing Agreement as the original Licensing Agreement.

NC : Non-commercial use, you may not use this work for commercial purposes.

For more information, please refer to:

Creative Commons — Attribution-NonCommercial-ShareAlike 3.0 Unported — CC BY-NC-SA 3.0

Project related features

In addition to being used for 12V desktop power banks, this project can also be used for:

Electric motorcycle and electric bicycle converters: LM5143 can serve as the core power management chip for electric motorcycle and electric bicycle converters, providing stable and efficient power.

High-voltage analog/digital system: suitable for analog or digital systems that require high-voltage power supply to ensure stable system operation.

Industrial control system: In industrial automation and control systems, LM5143 can provide the required high-voltage and high-current power supply to ensure the reliability of the system.

Telecommunications power system: As a power management solution for telecommunications base stations, it ensures stable power supply for communication equipment.

Ethernet POE: In Power Over Ethernet (POE) applications, the LM5143 can provide the required power management capabilities.

Portable mobile devices: Provide efficient power solutions for portable devices to extend device usage time.

Inverter system: Use LM5143 in the inverter system to achieve efficient energy conversion and power management.

Item properties

This project is the first public announcement and is my original project. The project has not won any awards in other competitions.

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At the beginning, I made at least two versions of EG1163S for the 12V30A360W power module, but it didn't work when powered on. Later, I switched to MK9218.

* Only 13A-14A was tested (I sent it later). I was so bad that I was lazy and chose a Texas Instruments model. (I changed it to 700W by the way.) Alas........................

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Choose one of the parallel inductors (L1, L3), (L2, L4), (L5, L7), or (L6, L8)

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* Clever colleagues have discovered that the LM5143 board can shrink from six to four layers.

Note that it is necessary to use a heating table for welding. If the soldering iron and hot air gun package cannot be welded, do not underestimate the power of copper direct connection.

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Hardware design

1. Minimum inductance calculation: lm5143 specification

Referring to page 42 (33) of the data sheet, Vout = 12V, Vin = 24V, Delta I = 60/4 * 0.3 = 4.5A, Fsw = 200KHz, we get Lmin = 6.667uH, here we take 6.8uH.

2. Use TI's calculation software (Excel): TI software

The compensation part has been slightly adjusted and did not fully follow the suggestions of "Little Software".

Taobao accessories

1. Fan 90 * 90 * 15-12V

2. Heat sink, width 98.5 * height 10 without sticker length 100mm

3. Thermal pad Taijino LV800-50 * 100 thickness 0.5

Other accessories

(Only one resistor is pasted here, not for thermal imaging.)

High power 600W aluminum shell resistor

Testing environment and equipment

Temperature: 21 ℃ -25 ℃

Humidity: 30% RH-60RH%

Air pressure: 1014mbar

Test equipment: 60V20A adjustable power supply (R-SPS6020-232), 200V60A500W electronic load, 600W 0.3Ω aluminum shell resistor (Taobao merchant pressed the terminal poorly, in the picture I crimped and tinned it myself), thermal imager (UTI260E +).

Heat dissipation performance

Picture naming convention: < input voltage > < output power >, for example: 36V500W is input 36V, output 12V500W.

Ripple performance

Modify

Improving heat dissipation performance: Step 1: After removing the heat sink, it was found that the main heating area of the PCB was not completely close to the heat dissipation surface due to the deflection of the PCB. After removing the thermal pads at both ends (retaining the middle horizontal MOS part of 50mm × 100mm), the temperature decreased from 109.9 ℃ to 76.2 ℃, a decrease of 33.7 ℃. (Please correct the heat dissipation temperature in the previous section) Step 2: Add a bolt hole in the middle of the PCB. Step 3: Increase the number of MOS vias from 4x4 to 7x7, and increase the number of LM5143 vias from 4x4 to 5x5.

2. At that time, I don't know why, I used a plug-in pin header, and now I have switched to a patch.

3. Delete the RC absorption at SW, because after increasing the RC absorption, the power-on MOS tube twitches, and the temperature "flickers" between 100 degrees Celsius and room temperature.

According to the data sheet, the sampling resistance of 58.4A should be 5mΩ, but the measured power limit is 500W. The reason is not yet clear, so the sampling resistance has been reduced. After testing, it can output 700W.

After the test, I impulsively tried 60V input and sent a board (powered on LM5143 warm, about 34 ℃) plus a TVS.