Single-Chip 150 W Af Power Amplifier

0 SINGLE-CHIP 150 W AF POWER AMPLIFIER The Type LM12 operational amplifier from National Semiconductor has at least one remarkable characteristic: its huge output current capability of about 10 A. The chip is housed in a 4-pin TO-3 enclosure, can handle peak powers up to 800 W, and has extensive internal pro- tective circuits to prevent damage caus- ed by current and voltage overloading, or by overheating. Peak operating tem- perature of the on-chip power output transistors is measured for controlling a limiter that forms part of a so-called dynamic safe area protection circuit. The power output stage is not connec- ted to the relevant pin until the supply voltage exceeds 14 V (±7 V). Output disconnection is automatic when the chip temperature rises above 150 °C. It is possible to connect LM12s in parallel, or in a bridge configuration, for very high power applications (voltage regulators, automotive drivers, stepper motor or power servo controllers, etc.). The present applicati...