TDA2005

Electrical specifications

Doc ID 1451 Rev 6

9/25

2.3.2

Bridge amplifier design

The following considerations can be useful when designing a bridge amplifier.

Where:

VCE sat = output transistors saturation voltage

VS = allowable supply voltage

RL = load impedance

Voltage and current swings are twice for a bridge amplifier in comparison with single ended

amplifier.

In other words, with the same RL the bridge configuration can deliver an output power that is

four times the output power of a single ended amplifier, while, with the same max output

current the bridge configuration can deliver an output power that is four times the output

power of a single ended amplifier, while, with the same max output current the bridge

configuration can deliver an output power that is twice the output power of a single ended

amplifier.

Core must be taken when selecting VS and RL in order to avoid an output peak current

above the absolute maximum rating.

From the expression for IOmax, assuming VS = 14.4 V and VCE sat = 2 V, the minimum load

that can be driven by TDA2005 in bridge configuration is:

The voltage gain of the bridge configuration is given by (see Figure 36):

Table 5.

Bridge amplifier design

Parameter

Single ended

Bridge

Vo max

Peak output voltage (before clipping)

Io max

Peak Output current (before clipping)

Po max

RMS output power (before clipping)

1

2

--- V

s

2V

CEsat

–



V

s

2V

CEsat

–

1

2

---

V

s

2V

CEsat

–

R

L

-----------------------------------

V

s

2V

CEsat

–

R

L

-----------------------------------

1

4

---

V

s

2V

CEsat

–



2

2R

L

-------------------------------------------

V

s

2V

CEsat

–



2

2R

L

-------------------------------------------

R

Lmin

V

s

2V

CEsat

–

I

Omax

------------------------------------

14.4

4

–

3.5

---------------------

2.97



==

=

G

v

V

0

V

1

-------

1

R

1

R

2 R4



R

2

R

4

+

---------------------







--------------------------

R

3

R

4

-------

++

==