TA3020 Ver la hoja de datos (PDF) - Unspecified

Número de pieza

componentes Descripción

Fabricante

TA3020

STEREO 300W (4Ω) CLASS-T DIGITAL AUDIO AMPLIFIER DRIVER USING DIGITAL POWER PROCESSING (DPP™ ) TECHNOLOGY

Unspecified 

Tripath Technology, Inc. - Technical Information

Over- and Under-Voltage Protection

The TA3020 senses the power rails through external resistor networks connected to VNNSENSE and

VPPSENSE. The over- and under-voltage limits are determined by the values of the resistors in the networks,

as described in the table “Test/Application Circuit Component Values”. If the supply voltage falls outside the

upper and lower limits determined by the resistor networks, the TA3020 shuts off the output stages of the

amplifiers. The removal of the over-voltage or under-voltage condition returns the TA3020 to normal operation.

Please note that trip points specified in the Electrical Characteristics table are at 25°C and may change over

temperature.

The TA3020 has built-in over and under voltage protection for both the VPP and VNN supply rails. The

nominal operating voltage will typically be chosen as the supply “center point.” This allows the supply voltage

to fluctuate, both above and below, the nominal supply voltage.

VPPSENSE (pin 29) performs the over and undervoltage sensing for the positive supply, VPP. VNNSENSE

(pin 30) performs the same function for the negative rail, VNN. When the current through RVPPSENSE (or

RVNNSENSE) goes below or above the values shown in the Electrical Characteristics section (caused by changing

the power supply voltage), the TA3020 will be muted. VPPSENSE is internally biased at 2.5V and VNNSENSE

is biased at 1.25V.

Once the supply comes back into the supply voltage operating range (as defined by the supply sense

resistors), the TA3020 will automatically be unmuted and will begin to amplify. There is a hysteresis range on

both the VPPSENSE and VNNSENSE pins. If the amplifier is powered up in the hysteresis band the TA3020

will be muted. Thus, the usable supply range is the difference between the over-voltage turn-off and under-

voltage turn-off for both the VPP and VNN supplies. It should be noted that there is a timer of approximately

200mS with respect to the over and under voltage sensing circuit. Thus, the supply voltage must be outside of

the user defined supply range for greater than 200mS for the TA3020 to be muted.

Figure 4 shows the proper connection for the Over / Under voltage sense circuit for both the VPPSENSE and

VNNSENSE pins.

V5

VNN

RVNN2

RVNN1

TA3020

30 VNNSENSE

V5

VPP

RVNN2 RVPP1

29 VPPSENSE

Figure 4: Over / Under voltage sense circuit

The equation for calculating RVPP1 is as follows:

R VPP1 = VPP

I VPPSENSE

Set R VPP2 = R VPP1 .

The equation for calculating RVNNSENSE is as follows:

20

TA3020 – KL Rev. 3.0/09.03

Share Link: