Power amplifier protection circuit, power amplifier, and speaker unit

摘要

The present invention is provided with: a first protection transistor (Q1), the emitter of which is connected to a first node (1); a first diode (D1) connected between the collector of the first protection transistor (Q1) and an output terminal (OUT); a second protection transistor (Q2), the emitter of which is connected to a second node (2); a second diode (D2) connected between the collector of the second protection transistor (Q2) and the output terminal (OUT); a first resistor (R1) and a thermistor (Th1), which are connected between the first node (1) and the second node (2); and a second resistor (R2) and a third resistor (R3), which are connected between the first node (1) and the collector of the second protection transistor (Q2). A voltage divided by means of the first resistor (R1) and the thermistor (Th1) is applied to the base of the second protection transistor (Q2), and a voltage divided by the second resistor (R2) and the third resistor (R3) is applied to the base of the first protection transistor (Q1).