Class H Linear Grounded Bridge Amplifier Output Stage
Superior audio performance for maximum output power with optimal efficiency
In order to accomplish high and stable power output such as 2500 W at 4 ohms, amplifiers have to deliver peak output voltages of up to 200 V. Linear push-pull concepts comprising a two-stage Class H topology are sensible solutions for output power of up to 1500 W at 4 ohms. The push-pull concept is limited by the 250 V specification of typical audio power transistors and their second breakdown restrictions. Even a short-term exceedance of the specified peak voltage or the second breakdown limit leads to a sudden breakdown of the power transistor and thus of the power amplifier.
The use of uncommon off-wall transistors with 350 V specification is no reliable solution for their second breakdown behavior, audio performance and also regarding their availability. Due to the Class AB amplifier kernel, Dynacord’s linear grounded bridge concept has been proven extremely reliable and superior in its audio performance over many years. One of the biggest advantages of grounded bridge solutions is a significantly reduced “voltage strain” on the power transistors.
This linear concept of a 3-stage Class H switch mode power supply enables the design of extremely efficient high power amplifiers featuring peak output power significantly over 200V and unparalleled audio performance. The image shows the switching behavior of an amplifier comprising floating 3-stage Class H technology. The amplifier’s dissipation power is proportional to the area (see picture, depicted in orange) between the operating voltage and the output signal. The smaller this area gets, the lower thermal loss of the power amplifier’s output transistors.