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

12

TCA2002 – KLi/0.95/04.06

It should be noted that only one channel of the modulator is required to create a bridged amplifier.

This is done by reversing the Y1 and Y1B connections to the second FET driver. This creates an out

of phase signal at HB OUTN with respect to HB OUTP.

A bridged amplifier has the advantage of potentially 4 times the output power for a given supply rail.

But the disadvantage is that the required number of FET drivers and MOSFETs per channel

increases by a factor of two.

The modulator feedback resistors are:

Ω

=

1K

typically

specified,

User

2)

-

(VPP

VPP

*

R

R

FBA

FBB

=

2

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 SINGLE-SUPPLY, BRIDGED OUTPUT operation:

Figure 5: Single Supply, Bridged Output (One Channel)

FET Driver

TCA2002

MOSFETS

Y1

Y1B

HIN1

LIN1

VPP

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