TPA005D14 datasheet(21/29 Pages) TI

21 / 29 page

TPA005D14

2-W STEREO CLASS-D AUDIO POWER AMPLIFIER

SLOS240A – AUGUST 1999 – REVISED MARCH 2000

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

APPLICATION INFORMATION

losses in a real-world class-D amplifier

Losses make class-D amplifiers nonideal, and reduce the efficiency below 100%. These losses are due to the

output transistors having a nonzero rDS(on), and rise and fall times that are greater than zero.

The loss due to a nonzero rDS(on) is called conduction loss, and is the power lost in the output transistors at

nonswitching times, when the transistor is ON (saturated). Any RDS(on) above 0 Ω causes conduction loss.

Figure 25 shows an H-bridge output circuit simplified for conduction loss analysis and can be used to determine

new efficiencies with conduction losses included.

VDD = 5 V

Ω

0.35

Ω

0.35

Ω

RDS(on)

RDS(off)

RDS(on)

5 M

Ω

5 M

Ω

Figure 25. Output Transistor Simplification for Conduction Loss Calculation

The power supplied, PSUP, is determined to be the power output to the load plus the power lost in the transistors,

assuming that there are always two transistors on.

Efficiency

+ h +

I2R

I2 2r

DS(on) )

I2R

Efficiency

+ h +

SUP

Efficiency

+ h +

DS(on) )

Efficiency

+ h + 95% at all output levels r

DS(on) +

0.1, R

L +

Efficiency

+ h + 85% at all output levels r

DS(on) +

0.35, R

L +

TPA005D14 Datasheet(PDF) 21 Page - Texas Instruments

TPA005D14 Datasheet(HTML) 21 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

Datasheet Download

Link URL