Tripath Technology, Inc. – Preliminary Technical Information

9

TPS4100 – KL/Rev. 2.5/02.05

Typical Performance AM Mode

100

0.01

0.02

0.05

0.1

0.2

0.5

1

2

5

10

20

50

%

1

2

5

10

20

50

100

W

AM MODE

R

f = 1Khz

BW = 22Hz - 20kHz(AES17)

THD+N versus Output Power

V

V

Efficiency and Power D issipation versus

Total output Power

0

10

20

30

40

50

60

70

80

020

30

40

Total Output Power (W )

50

60

0

15

30

60

45

10

AM MOD E

V

R

f= 1kH z

BW = 22H z - 20kH z(AES17)

Power Dissipation

Efficiency

70

80

90

100

Application Information

GENERAL DESCRIPTION

The TPS4100 is a 4-channel BTL (Bridge Tied Load) audio amplifier power stage that operates on a

single supply voltage ranging from 10-26V. The device is targeted specifically to meet the demands of

OEM and aftermarket automobile in-dash head units. With a single supply voltage of 25V, the device

delivers four 100 Watt (saturated square wave) channels into 4 ohm. Since the TPS4100 is a switching

amplifier, the average dissipation at low to medium output power is far superior to best in class AB

amplifiers specifically designed for in-dash head units.

POWER SUPPLY REQUIREMENTS

The device is configured to operate from a single supply voltage of 10-26V. This allows the device to

operate from an automobile battery under various conditions including: battery voltage with the engine off,

alternator voltage with engine running and boosted voltage operation up to 26V using a DC-DC converter

or voltage booster. The sleep pin must be driven from a microcontroller or external 3.3V or 5.0V power

supply.

AM MODE

When used in conjunction with a Class-T controller, such as TCD6001, the TPS4100 is configured as a

high power, high efficiency, four channel switching amplifier. The TPS4100 also has an additional

amplifier mode named “AM Mode.” By pulling the AM pin to a logic high level, the amplifier is configured

as a Class B amplifier as opposed to the normal, Class-T amplifier.

AM mode significantly reduces EMI generation since the output amplifiers are now operated in linear

mode. Operating in Class B mode also reduces the TPS4100 efficiency especially at low to medium

output powers. Due to this increased power dissipation, it is recommended that the AM mode is used for

applications such as AM radio playback where the average output level is minimal and a switching

amplifier would most effect radio reception.