RM supercapacitor controller Model Ling - PSP Team

Note: This version has defects. It is recommended to use the latest version. This version features
a supercapacitor main controller, Model Ling
, with low-code development and an ultra-small bidirectional four-switch module – only 38x50mm, about half the size of a bank card.
Still not small enough? The third-generation four-switch supercapacitor module is only 30.9x40mm. Open source is on the way, stay tuned.
Author: Luolin ltyxh - bilibili Pacific Spirit (PSP) team
. The switching frequency can be adjusted with resistors. 400 or 600kHz is recommended.

The standard bidirectional four-switch Buck-boost (FSBB) structure
requires at least two layers (four layers are recommended to meet overcurrent capacity). The single-sided component
inductance and wiring overcurrent capacity should not be less than 13A.
Low BOM cost, single-board component cost within 25 yuan.

This design uses the SC8802 main controller with built-in 2A driver and controller. The main controller's maximum design voltage is 35V and 30V (overvoltage protection), and dynamic current limiting can be controlled via PWM signals to achieve chassis power control. The amount of development code is much smaller than that of a regular design. See the datasheet for details.
The device

contains 0402 resistors and capacitors and a 0.4mm QFN package, which presents soldering challenges. The project's BOM is relatively standardized and includes many standard library components; partial surface mount technology (SMT) can be considered if necessary.
The CJNC100S08L exhibits significant heat generation, possibly due to its large gate capacitance leading to high switching losses. Replacing the MOSFET or reducing the switching frequency to 400kHz could improve efficiency.
Under no-load conditions, the output voltage is prone to overshoot, triggering overvoltage protection. Without load, the SC8802 may continuously trip and restart its protection.