LA4440

No.750–5/13

Voltage Gain Adjust at Stereo Mode

VG=20log

(dB)

VG=20log

(dB)

VG

Rf

Voltage Gain Adjust at Bridge Amplifier Mode (No. 1)

· The bridge amplifier configuration is as shown left, in

which ch1 and ch2 operate as noninverting amplifier

and inverting amplifier respectively.

The output of the noninverting amplifier divided by

resistors R3, R4 is applied, as input, to the inverting

amplifier.

Since attenuation (R4/R3) of the non-inverting amplifier

inverting amplifier are fixed to be the same, signals of

the same level and 180

° out of phase with each other

can be obtained at output pins (12) and (10). The total

voltage gain is apparently higher than that of the

noninverting amplifier by 6dB and is approximately

calculated by the following formula.

VG=20log

+ 6dB

to the noninverting amplifier side only and the following

formula is used.

VG=20log

+ 6dB

VG=20log

(dB)

causes the voltage gain to be reduced at the modes of

both stereo amplifier and bridge amplifier.

Voltage Gain Adjust at Bridge Amplifier Mode (No. 2)

2