Class G vs. Class H Amplifiers: Key Differences

There are several classes of amplifiers, including Class A, Class B, Class AB, Class C, Class G, and Class H. In this article, we’ll dive into a comparison of Class G and Class H amplifiers, highlighting the key differences between these two types. For a broader understanding, you might also want to explore the differences between Class A, B, AB, and C amplifiers.

Class G Amplifier

• Class G amplifiers share similarities with Class AB amplifiers.
• The key distinction lies in their use of two or more supply voltages.
• At low signal levels, they operate using a lower supply voltage.
• As the signal level increases, the Class G amplifier intelligently selects the appropriate supply voltage to power its operation.
• Class G amplifiers are more efficient compared to Class AB amplifiers.
• This efficiency stems from the fact that Class G amplifiers only utilize the maximum supply voltage when it’s truly necessary, while Class AB amplifiers constantly operate with the maximum supply voltage.

Class H Amplifier

• Class H amplifiers modulate the supply voltage for the devices connected to the amplifier’s output.
• This modulation ensures that the supply voltage is always just a little less than what’s needed to support the signal swing.
• This approach helps to minimize dissipation across the output devices connected to the supply.
• As a result, the amplifier operates at an efficiency level comparable to an optimized Class AB design, regardless of the output power level.
• Class H amplifiers tend to be more complex than other amplifier designs.
• This complexity arises from the need for extra control circuits to predict and manage the supply voltage effectively.

Key Differences Summarized