TS4990 1.2 W audio power amplifier with active-low standby mode Features

TS4990 Application information

The graph in

Figure 60

shows an example of C in

and C feed

influence.

Figure 60.

Frequency response gain vs. C in

and C feed

10

5

0

-5

-10

-15

-20

-25

10

Cfeed = 330pF

Cfeed = 680pF

Cin = 470nF

Cfeed = 2.2nF

Cin = 22nF

Cin = 82nF

100

Frequency (Hz)

Rin = Rfeed = 22k

Ω

Tamb = 25

°

C

1000 10000

4.4 Power dissipation and efficiency

Hypotheses:

●

●

Load voltage and current are sinusoidal (V out

and I out

).

Supply voltage is a pure DC source (V

CC

).

The load can be expressed as:

V out

=

V

PEAK

sin

ω t (V) and

I out

=

V

------------ (A)

R

L and

P out

=

V

2R

L

2

(W)

Therefore, the average current delivered by the supply voltage is:

I

CC

AVG

=

2

V

π

R

L

(A)

The power delivered by the supply voltage is:

P supply

= V

CC

⋅

I

CC

AVG

(W)

Doc ID 9309 Rev 13 19/33