To provide higher audio output powers in the automotive environment, a boosted rail is required which usually generates voltage between 18 and 60V.
Often this voltage is adjusted in accordance with the output signal resulting in Class-H or enhanced Class-D designs.
Ususally the boosted voltage rail is generated and controlled by an analogue voltage regulator IC working in push-pull or boost topology. For Class-H amplifiers the target output voltage can be changed using a PWM signal or by changing the feedback loop using GPIOs of a microcontroller and some resistors.
These analogue voltage regulators work with a fixed compensation loop, hence their regulation speed is always the same – no matter if a low frequency high energy punch is output through the speakers or a low noise high frequency periodival sinewave. Hence the compensation is always a compromise to cover the requested energy of all possible output signals resulting in lower power efficiency, more noise and worse EMC.
crispAudio has developed InnoPower to fully control the output voltage in SW – not only the target voltage but also the regulation speed by estimating the upcoming output energy on base of the audio signal.
Furthermore InnoPower eliminates the cost of the analogue voltage regulator IC as the existing system microcontroller is used for running the control loop.
InnoPower just requires two ADC channels and a PWM output channel to realize a forward-thinking power supply which can work “ahead of time” which enables higher peak output power, better thermal efficiency, less audible noise and better EMC.
InnoPower can work in boost, push-pull and pure inversion topologiy and is independant of the required output voltage and power.