Class D Amplifier IC BD5460
BD5460 is a low power Class D amplifier that can be used in low power applications like handheld audio devices. BD5460 does not require an LC filter at the speaker output and can be driven using a battery, The standby current of BA5460 is typically zero and there is no switch ON / OFF clicks. The BD5460 can deliver 0.8 watts into an 8 ohm speaker at 3.6 V supply voltage. The power supply voltage range is from 2.5 to 6.5 V DC. The IC has a built-in standby function, short circuit protection, thermal shutdown and under voltage lockout.
Class D amplifier is a type of amplifier where the power devices (MOSFET or transistor) are operated as switches. There will be only two states (ON/OFF) for these switches and no time is wasted for the transition from one stage to another. The working of a class D amplifier is as follows. At first the audio signal to be amplified compared with a high frequency triangle waveform and the result will be a square wave whose duty cycle is proportional to the input audio level. This square wave is then fed to the gate of the switching element (MOSFET) for power amplification. The then the audio signal is retrieved from the amplifier square wave using an LC filter.