1998-09-08 , E/IC-1026/54
Product News From Philips Semiconductors

Philips Semiconductors, the largest European semiconductor manufacturer, has introduced a new high-efficiency Class-H audio power amp IC that delivers an output power of 70W into a 4-ohm bridge tied load from a 14.4 V supply. Even at 12 V it can deliver 50 W outputs, while on a 17 V supply it produces an incredible 100 W of peak power from its standard plastic power package with minimal heatsinking. Targeted at applications such as car radios, active speakers, sub-woofers and home audio systems, the  TDA1562Q meets the market demand for high music power output, while at the same time conserving energy resources*.

"Compared to conventional Class A-B amplifiers, the TDA1562Q delivers four times the output power for half the power dissipation" explained product marketing manager Wladimir Punt.

Because of its high efficiency operation, heatsinks for the TDA1562Q can be smaller than those for Class-AB designs, reducing the size, weight and cost of audio equipment. And because less supply power is required to generate the same output power, use of this new power amp IC also simplifies power supply design.

The TDA1562Q is fully protected against thermal overloads, automatically switching to Class-AB operation if the case temperature exceeds 120&176;C. It is also fully protected against short circuits across its bridge outputs and between its outputs and either supply rail. By turning off its output stages under these fault conditions, power dissipation drops to a very low level. In addition, the output is automatically muted if the supply voltage drops below an acceptable level.

To meet the demands of intelligent output power control, the TDA1562Q also features on-chip diagnostic and status reporting capabilities. Its status output indicates the current mode of operation (Class-H, Class-AB or muted), while its diagnostic pin provides information about short-circuit, load disconnection and over-temperature conditions. In addition, the TDA1562Q incorporates a dynamic distortion detector that reports the onset of output clipping, allowing interactive use of a sound processor or automatic gain control to preserve audio quality.

The TDA1562Q is packaged in a 17-lead single-in-line (SIL) plastic power package with its leads pre-formed to a dual-in-line (DIL) format. Samples are available now, with full production scheduled to begin in the fourth quarter of 1998. As a guide to pricing, the TDA1562Q will sell for around US$ 3.50 in high volume.

Philips Semiconductors, a division of Koninklijke Philips Electronics NV, headquartered in Eindhoven, The Netherlands, is the ninth largest semiconductor supplier in the world. Philips Semiconductors' innovations in digital audio, video, and mobile technology position the company as a leader in the consumer, multimedia and wireless communications markets. Sales offices are located in all major markets around the world and are supported by regional customer application labs.

Technical Note - Class-H Operation

Class-H audio power amplifiers normally operate in conventional Class-AB mode until higher output powers are needed, at which point they momentarily boost the power level to their output stages using the charge stored in a capacitor. Because no DC/DC conversion is required, this technique reduces the external component count and eliminates the problems of EMI radiation.

* As part of Philips' company-wide EcoVision strategy, more and more products from Philips Semiconductors will be designed with energy-efficiency in mind to protect the world's energy resources.