Outline
YDA135 is digital audio power amplifier controller IC that is output power of 20W/channel on a 12V power supply operation.
This IC is combined with the general purpose Power MOSFET (hereafter called Power MOSFET) that are connected through BTL can configure an audio power amplifier with output power of 5W or 20W. This IC accepts analog signal, converts it into digital pulse signal by the digital modulation circuitry and outputs the digital pulse signal for driving Power MOSFET. The Power MOSFET that is driven by this IC outputs large current digital pulses. The digital pulse signal is converted to audio signal through an external low pass filter, and sent to the speakers.

By using a general purpose Power MOSFET, very low cost digital amplifier system is configured. By adapting Yamaha's proprietary modulation system, the device provides low distortion and high signal to noise ratio at the highest level among digital amplifiers in the equiralent class.
This IC has the overcurrent detection function that detects overcurrent state by voltage drop of external resistors that detects the output current.
This IC has the high temperature detection function that detects high temperature by resistor value change of external element that detects temperature.

The operation of this IC is limited by using two control signal, SLEEP or MUTE. SLEEP signal stops all functions of this IC, and restrain to the power consumption at the minimum. MUTE signal brings Power MOSFET into nonconductive state, and mute the output of the device.
This IC is configured by two power supply ; 5V for signal processing circuits, and 12V for Power MOSFET driving circuits.