Q: What is Over Temperature Protection (OTP) and Short circuit protection (SCP) shutdown in audio power amplifiers?
A: Many TI audio power amplifiers are designed with thermal (OTP) and Short circuit protection (SCP). In OTP, most amplifiers will shutdown automatically when the die temperature exceeds the thermal threshold (usually 150C) and recovery automatically once the temperature drops below a specified temperature. For SCP, many amplifiers are designed with a latched shutdown protection, i.e. they shutdown and stays in shutdown until power or SDZ is cycled. However, SCP in some newer amplifiers, eg TPA312xD2, are designed with auto-recovery. The best way to distinguish between OTP and SCP is to look at the switching outputs with a scope. SCP will auto-recover at a fixed rate (i.e. every 250ms). OTP usually recovers a lot slower and the rate depends on how high the temperature of the die & ambient is.