Chip Set Chops Parts, Board Size in Half

An IRS20955 200V digital audio driver IC and the IRFI4024Hx series of digital audio MOSFETs comprise a new Class D audio chip set developed by International Rectifier. Compared to typical designs, the new IC reduces pcboard space by 50% for Class D audio amplifiers up to 500W, while the MOSFETs reduce power switch part count of the Class D stage by 50% for the mid-voltage range of mid- and high-power amplifiers, says the company.

The IRS20955(S)(TR)PBF IC reduces external component count by up to 27 components. It features a floating, 3.3V/5V, logiccompatible, PWM input that eliminates seven external level-shift components for Class D audio applications. That’s because it employs a half-bridge topology and dual power supply.

Greater protection is achieved with an integrated programmable, bidirectional, current-sensing feature with self-reset function. It allows the high-voltage IC to sense the exact point of the switching cycle. Because current is sensed at the correct moment, the IC can optimise the overcurrent protection circuit. This offers considerable space-saving benefits thanks to the elimination of a large current-sense resistor.

In addition, the audio driver incorporates protection control logic that eliminates 11 components and shrinks board footprint when compared with other audio IC reference designs.

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