Tri p ath Techn o l o g y, I n c. - T echn i cal I n fo rmation

11

TCA2002 – KLi/0.95/04.06

half-bridge output and load ground. The resistor divider networks at the TCA2002 scale the feedback

signals. The resistor values are determined based on the supply voltage, as explained below.

The modulator feedback resistors are:

Ω

=

1K

typically

specified,

User

4)

-

(VPP

VPP

*

R

R

FBA

FBB

=

4

VPP

*

R

R

FBA

FBC

=

1

R

*

R

)

R

(R

*

R

A

FBB

FBA

FBB

FBA

FBC

MODULATOR

-

V

+

+

≈

The above equations assume that VPP=|VNN|.

The resultant modulator gain is:

30.02V/V

1

1.07k Ω

*

1.0k Ω

)

1.07k

(1.0k Ω

*

15.0k Ω

MODULATOR

-

AV

=

+

Ω

+

≈

For SPLIT-SUPPLY, BRIDGED OUTPUT operation:

Figure 4: Split Supply, Bridged Output (One Channel)

Figure 4 shows the basic split supply, bridged output amplifier using a TCA2002. The MOSFET

output stage operates from two power supplies, VPP and VNN, that are equal magnitude, but

opposite polarity (for instance +/-60VDC).

Both terminals of the speaker are actively driven.

Differential feedback is taken from each half-bridge output. The resistor divider networks at the

TCA2002 scale the feedback signals. The resistor values are determined based on the supply

voltage, as explained below.

FET Driver

TCA2002

MOSFETS

Y1

Y1B

HIN1

LIN1

VPP

VNN

FBKN1

FBKP1

HB OUTP

R

FBB

V5

R

FBC

R

FBB

V5

R

FBC

HS OUT1

LS OUT1

HS GATE1

LS GATE1

HS OUT2

LS OUT2

HS GATE2

LS GATE2 HB OUTN

HIN2

LIN2