TS4851 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

TS4851

Mono 1W Speaker and Stereo 160mW Headset BTL Drivers with Digital Volume Control

STMicroelectronics 

TS4851

Application Information

5 Application Information

5.1 BTL configuration principles

The TS4851 integrates 3 monolithic power amplifier having BTL output. BTL (Bridge Tied Load) means

that each end of the load is connected to two single-ended output amplifiers. Thus, we have:

Single ended output 1 = Vout1 = Vout (V)

Single ended output 2 = Vout2 = -Vout (V)

and

Vout1 - Vout2 = 2Vout (V)

The output power is:

Pout = (2 Vout RMS )2 (W)

RL

For the same power supply voltage, the output power in BTL configuration is four times higher than the

output power in single ended configuration.

5.2 Power dissipation and efficiency

Hypotheses:

l Voltage and current in the load are sinusoidal (Vout and Iout).

l Supply voltage is a pure DC source (Vcc).

Regarding the load we have:

VO UT = VPEAK sin ω t (V)

and

IOUT = -V----O----U----T--- (A)

RL

and

PO UT = V-----P---E----A---K----2--- (W)

2RL

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

I CC AVG =

2 V-----P---E----A----K--- (A)

πRL

The power delivered by the supply voltage is:

Psupply = Vcc IccAVG (W)

Then, the power dissipated by each amplifier is

Pdiss = Psupply - Pout (W)

Pdiss

=

2 2 VCC

π RL

POUT − POUT

(W)

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