Dual-channel small-size fixed-output DC-DC step-down module based on EG1163S

This project is the first version of the gimbal power supply, designed for continuous 6*2A load operation 24/7 on a DJI battery.
It boasts extremely high cost-effectiveness, extremely high power density, relatively comprehensive protection, and no need for additional cooling. However,
it has drawbacks such as relatively high voltage ripple (83mV at full load), still relatively high heat generation (not tested under 24/7 full load), and a fixed output of only 19V.
Advantages:
High cost-effectiveness: Using free prototyping from LCSC, the component price (excluding XT30) is only around 14 RMB.
High power density: The board size is only 4.7*4.7cm, providing 19V 7A*2 (still being optimized, replacing MOSFETs, reducing gate resistance, etc.).
Protection measures: Using 5*6 packaged PMOS for reverse connection protection, high-side current sensing, setting output current thresholds, and EN undervoltage lockout to protect the battery.
Disadvantages:
Ripple does not meet requirements (below 100mV at full load), heat generation reaches 85 degrees Celsius, unsuitable for long-term stable operation. Gate rise time is too long, resulting in weak chip driving capability.
Improvement directions:
1. Use MOSFETs with smaller QG. The CSD18540 is used in this case, with a QG of 42nc, which is insufficient for driving the EG1163.
2. Connect a DAC interface to the feedback terminal for easy voltage adjustment.
3. Implement voltage and current detection at the output terminal for convenient microcontroller closed-loop control. 4.
Optimize the layout with larger openings to enhance heat dissipation.
5. Install electrostatic discharge (ESD) and TVS devices to ensure operational stability.
Note: The part number (MMB) is not entirely accurate; for example, the inductor value is 15uH. If copying, please carefully verify the information.
 
Efficiency: Input 146W, Output 140W (including line loss), efficiency 96%.
 
Update 1: After replacing the CSD18540 with an NTMS4C06N, the single-channel continuous load capacity without heat dissipation reaches 19V 8.9A. The gate resistor is 6.8Ω.
Below are test images.
Update 2: Previously, the ripple measurement did not have the 20M bandwidth limit enabled. After enabling it, the ripple measured at a 7A load was 83.5mV, meeting the usage requirements.
Update 3: Upgraded to a four-layer board, obtaining a complete ground plane!!!
7.5A temperature measurement