The Class D speaker amp's drive output stage utilizes high efficiency PWM drive (H or L) based on the output signal level. This results in low power loss and high efficiency (85-90%).In contrast, conventional analog amps feature Class AB output, requiring (among other things) a bias current. The result is low efficiency and high heat generation, requiring an external heat sink.
Besides high efficiency and low heat generation, ROHM Class D speaker amps provide a number of advantages: 1.High fidelity (low noise, low distortion) 2.Popping noise eliminated (via soft mute function) 3.Multiple protection functions built in (preventing IC/speaker damage)
Based on the application a simple filter (i.e. ferrite beads, ceramic capacitor) can be used. For example, active speakers used for compact LCDs or iPod docks are products that use short speaker cables, while large-screen LCDs require longer speaker cables, resulting in the generation of unwanted radiation (EMI) requiring countermeasures (i.e. filters).
Of course. Speaker output power is determined by VCC (supply voltage) and the speaker load (in ohms). 20W output results from a supply voltage of 18V and a speaker load of 8Ω. For 10W output the conditions are: 13V VCC and 8Ω speaker load.
It is the abbreviation of Bridge Tied Load. It reverses the speaker both terminals to connect by using two amplifier circuits compared with a usual single amplifier. If without output coupling capacitor,it may has an advantage that output electric power quadruples.