Upc1237 Speaker Protection Board (compatible With The Btl Protection) - Instrument Parts & Accessories - AliExpress
UPC1237 Power Amplifier Speaker Protection Circuit Board Boot Delay DC Protection Support BTL Power Amplifier Board|Instrument Parts & Accessories| - AliExpress
DIYfan: Speaker protection with uPC1237
DIY Speaker Protection uPC1237 with speaker terminal schematic and Komitart LAY6.
Speaker protection circuit with PCB layout - ElecCircuit.com