TS488(2019) 查看數據表（PDF） - STMicroelectronics

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TS488
(Rev.:2019)

Pop-free 120 mW stereo headphone amplifier

STMicroelectronics 

5

Application information

TS488

Application information

5.1

Power dissipation and efficiency

Hypotheses:

• Voltage and current in the load are sinusoidal (Vout and Iout)

• Supply voltage is a pure DC source (VCC)

Regarding the load, we have:

VOUT = VPEAKsin ωt(V)

(1)

and

IOUT

=

VOUT

RL

(A)

(2)

and

POUT

=

V2PEAK

2RL

(A)

(3)

The average current delivered by the power supply voltage is:

ICCAVG

=

1

2π

∫0π

VPEAK

RL

sin(t)dt

=

VPEAK

πRL

(A)

(4)

Figure 74. Current delivered by power supply voltage in single-ended configuration

Icc (t)

Vpeak/LR

IccAVG

0

T/2

T

3T/2

2T Time

The power delivered by power supply voltage is:

Psupply = VCCICCAVG(W)

So, the power dissipation by each power amplifier is:

Pdiss = Psupply−POUT(W)

Pdiss =

2VCC

π RL

POUT − POUT(W)

and the maximum value is obtained when:

∂Pdiss

∂POUT

=

0

and its value is:

DS4579 - Rev 7

(5)

(6)

(7)

(8)

page 20/32

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