![[Under Construction]](images/undercon.gif){kind=small}
Harris CoolAudioİ Class-D switching amplifier
INTRODUCTION
This amplifier was constructed a long time ago, when the HIP4080 MOSFET driver was first made available. If I remember some of the details wrongly, please forgive me!
DESCRIPTION
The HIP4080 is a bit more fussy about power supplies. It requires a 5v supply for the logic circuitry, 12v supply for the MOSFET driver stage, and about 30v for the external power MOSFETs for an output power of about 100watts into an 8ohm load. The logic and driver supplies are handled by generic LM7805/12 voltage regulators, while the main supply is taken from a lab power supply.
The HIP4080 requires a triangle wave input for it's input comparator to generate a PWM wave. I used a 74LS14 Schmitt trigger inverter to generate the required pulse, then used a UA741 op-amp to integrate the pulse wave into a triangle wave. I used IRF610's for the output stage because there were a few lying around. The output stage is shunted to ground by a single 0.68uF polypropylene capacitor. I didn't want to spend too much money buying inductors!
SOUND QUALITY
What can I say? Very harsh sounding, probably because I did not use the output inductors, but I did not want to investigate further. Bass is fairly tight, characteristic of Class-D amplifiers. I would imagine this amplifier being used in some (cheap?) commercial subwoofers, due to small size and low cost. Also, they probably cannot match the sound quality of most analog amplifiers.
PICTURES
