Philips (Now NXP) TDA8920BJ, TDA8920BTH Schematic [ru]

Name: Philips (Now NXP) TDA8920BJ
Brand: Philips (Now NXP)
SKU: 3781308
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1. General description

The TDA8920B is a high efﬁciency class-D audio power ampliﬁer with very low

dissipation. The typical output power is 2 × 100 W.

The device is available in the HSOP24 power package and in the DBS23P through-hole

power package. The ampliﬁer operates over a wide supply voltage range from

±12.5 V to ±30 V and consumes a very low quiescent current.

2. Features

■ Zero dead time switching

■ Advanced current protection: output current limiting

■ Smooth start-up: no pop-noise due to DC offset

■ High efﬁciency

■ Operating supply voltage from ±12.5 V to ±30 V

■ Low quiescent current

■ Usable as a stereo Single-Ended (SE) ampliﬁer or as a mono ampliﬁer in Bridge-Tied

Load (BTL)

■ Fixed gain of 30 dB in Single-Ended (SE) and 36 dB in Bridge-Tied Load (BTL)

■ High output power

■ High supply voltage ripple rejection

■ Internal switching frequency can be overruled by an external clock

■ Full short-circuit proof across load and to supply lines

■ Thermally protected.

3. Applications

■ Television sets

■ Home-sound sets

■ Multimedia systems

■ All mains fed audio systems

■ Car audio (boosters).

TDA8920B

2 × 100 W class-D power ampliﬁer

Rev. 01 — 1 October 2004 Preliminary data sheet

Preliminary data sheet Rev. 01 — 1 October 2004 2 of 34

Philips Semiconductors

TDA8920B

2 × 100 W class-D power ampliﬁer

4. Quick reference data

5. Ordering information

Table 1: Quick reference data

Symbol Parameter Conditions Min Typ Max Unit

General; V

= ±27 V

supply voltage ±12.5 ±27 ±30 V

q(tot)

total quiescent

supply current

no load; no ﬁlter; no RC-snubber

network connected

-5065mA

Stereo single-ended conﬁguration

output power R

=3Ω; THD = 10 %; V

= ±27 V - 110 - W

=4Ω; THD = 10 %; V

= ±27 V - 86 - W

Mono bridge-tied load conﬁguration

output power R

=6Ω; THD = 10 %; V

= ±27 V - 210 - W

Table 2: Ordering information

Type number Package

Name Description Version

TDA8920BTH HSOP24 plastic, heatsink small outline package; 24 leads; low

stand-off height

SOT566-3

TDA8920BJ DBS23P plastic DIL-bent-SIL power package; 23 leads (straight

lead length 3.2 mm)

SOT411-1

Preliminary data sheet Rev. 01 — 1 October 2004 3 of 34

Philips Semiconductors

TDA8920B

2 × 100 W class-D power ampliﬁer

6. Block diagram

Pin numbers in parenthesis refer to the TDA8920BJ.

Fig 1. Block diagram.

coa023

OUT1

SSP1

DDP2

DRIVER

HIGH

OUT2

BOOT2

TDA8920BTH

(TDA8920BJ)

BOOT1

DRIVER

LOW

RELEASE1

SWITCH1

ENABLE1

CONTROL

AND

HANDSHAKE

PWM

MODULATOR

MANAGER

OSCILLATOR

TEMPERATURE SENSOR

CURRENT PROTECTION

VOLTAGE PROTECTION

STABI

MODE

INPUT

STAGE

mute

9 (3)

8 (2)

IN1M

IN1P

22 (15)

21 (14)

20 (13)

17 (11)

16 (10)

15 (9)

SSP2

SSP1

DRIVER

HIGH

DRIVER

LOW

RELEASE2

SWITCH2

ENABLE2

CONTROL

AND

HANDSHAKE

PWM

MODULATOR

11 (5)

SGND1

7 (1)

OSC

2 (19)

SGND2

6 (23)

MODE

INPUT

STAGE

mute

5 (22)

4 (21)

IN2M

IN2P

19 (-)24 (17)

SSD

n.c.

1 (18)

SSA2

12 (6)

SSA1

3 (20)

DDA2

10 (4)

DDA1

23 (16)13 (7)18 (12) 14 (8)

DDP2

PROTSTABI

DDP1

Preliminary data sheet Rev. 01 — 1 October 2004 4 of 34

Philips Semiconductors

TDA8920B

2 × 100 W class-D power ampliﬁer

7. Pinning information

7.1 Pinning

7.2 Pin description

Fig 2. Pin conﬁguration TDA8920BTH. Fig 3. Pin conﬁguration TDA8920BJ.

TDA8920BTH

SSD

SSA2

DDP2

SGND2

BOOT2 V

DDA2

OUT2 IN2M

SSP2

IN2P

n.c. MODE

STABI OSC

SSP1

IN1P

OUT1 IN1M

BOOT1 V

DDA1

DDP1

SGND1

PROT V

SSA1

001aab217

TDA8920BJ

OSC

IN1P

IN1M

DDA1

SGND1

SSA1

PROT

DDP1

BOOT1

OUT1

SSP1

STABI

SSP2

OUT2

BOOT2

DDP2

SSD

SSA2

SGND2

DDA2

IN2M

IN2P

MODE

001aab218

Table 3: Pin description

Symbol Pin Description

TDA8920BTH TDA8920BJ

SSA2

1 18 negative analog supply voltage for channel 2

SGND2 2 19 signal ground for channel 2

DDA2

3 20 positive analog supply voltage for channel 2

IN2M 4 21 negative audio input for channel 2

IN2P 5 22 positive audio input for channel 2

MODE 6 23 mode selection input: Standby, Mute or Operating mode

OSC 7 1 oscillator frequency adjustment or tracking input

IN1P 8 2 positive audio input for channel 1

IN1M 9 3 negative audio input for channel 1

DDA1

10 4 positive analog supply voltage for channel 1

Preliminary data sheet Rev. 01 — 1 October 2004 5 of 34

Philips Semiconductors

TDA8920B

2 × 100 W class-D power ampliﬁer

8. Functional description

8.1 General

The TDA8920B is a two channel audio power ampliﬁer using class-D technology.

The audio input signal is converted into a digital Pulse Width Modulated (PWM) signal via

an analog input stage and PWM modulator. To enable the output power transistors to be

driven, this digital PWM signal is applied to a control and handshake block and driver

circuits for both the high side and low side. In this way a level shift is performed from the

low power digital PWM signal (at logic levels) to a high power PWM signal which switches

between the main supply lines.

A 2nd-order low-pass ﬁlter converts the PWM signal to an analog audio signal across the

loudspeakers.

The TDA8920B one-chip class-D ampliﬁer contains high power D-MOS switches, drivers,

timing and handshaking between the power switches and some control logic. For

protection a temperature sensor and a maximum current detector are built-in.

The two audio channels of the TDA8920B contain two PWMs, two analog feedback loops

and two differential input stages. It also contains circuits common to both channels such

as the oscillator, all reference sources, the mode functionality and a digital timing

manager.

The TDA8920B contains two independent ampliﬁer channels with high output power,high

efﬁciency, low distortion and a low quiescent current. The ampliﬁer channels can be

connected in the following conﬁgurations:

• Mono Bridge-Tied Load (BTL) ampliﬁer

• Stereo Single-Ended (SE) ampliﬁers.

SGND1 11 5 signal ground for channel 1

SSA1

12 6 negative analog supply voltage for channel 1

PROT 13 7 decoupling capacitor for protection (OCP)

DDP1

14 8 positive power supply voltage for channel1

BOOT1 15 9 bootstrap capacitor for channel 1

OUT1 16 10 PWM output from channel 1

SSP1

17 11 negative power supply voltage for channel 1

STABI 18 12 decoupling of internal stabilizer for logic supply

n.c. 19 - not connected

SSP2

20 13 negative power supply voltage for channel 2

OUT2 21 14 PWM output from channel 2

BOOT2 22 15 bootstrap capacitor for channel 2

DDP2

23 16 positive power supply voltage for channel 2

SSD

24 17 negative digital supply voltage

Table 3: Pin description

…continued

Symbol Pin Description

TDA8920BTH TDA8920BJ

Preliminary data sheet Rev. 01 — 1 October 2004 6 of 34

Philips Semiconductors

TDA8920B

2 × 100 W class-D power ampliﬁer

The ampliﬁer system can be switched in three operating modes with pin MODE:

• Standby mode; with a very low supply current

• Mute mode; the ampliﬁers are operational; but the audio signal at the output is

suppressed by disabling the VI-converter input stages

• Operating mode; the ampliﬁers are fully operational with output signal.

To ensure pop-noise free start-up the DC output offset voltage is applied gradually to the

output between Mute mode and Operating mode. The bias current setting of the VI

converters is related to the voltage on the MODE pin; in Mute mode the bias current

setting of the VI converters is zero (VI converters disabled) and in Operating mode the

bias current is at maximum. The time constant required to apply the DC output offset

voltage gradually between mute and operating can be generated via an RC-network on

the MODE pin. An example of a switching circuit for driving pin MODE is illustrated in

Figure 4. If the capacitor C is left out of the application the voltage on the MODE pin will

be applied with a much smaller time-constant, which might result in audible pop-noises

during start-up (depending on DC output offset voltage and used loudspeaker).

In order to fully charge the coupling capacitors at the inputs, the ampliﬁer will remain

automatically in the Mute mode before switching to the Operating mode. A complete

overview of the start-up timing is given in Figure 5.

Fig 4. Example of mode selection circuit.

001aab172

SGND

MODE pin

mute/on

5 V

standby/

mute

Preliminary data sheet Rev. 01 — 1 October 2004 7 of 34

Philips Semiconductors

TDA8920B

2 × 100 W class-D power ampliﬁer

When switching from standby to mute, there is a delay of 100 ms before the output starts

switching. The audio signal is available after V

mode

has been set to operating, but not earlier

than 150 ms after switching to mute. For pop-noise free start-up it is recommended that the

time constant applied to the MODE pin is at least 350 ms for the transition between mute and

operating.

When switching directly from standby to operating, there is a ﬁrst delay of 100 ms before the

outputs starts switching. The audio signal is available after a second delay of 50 ms. For

pop-noise freestart-up it is recommended that the time constant applied to the MODE pin is at

least 500 ms for the transition between standby and operating.

Fig 5. Timing on mode selection input.

2.2 V < V

mode

< 3 V

audio output

operating

standby

mute

50 %

duty cycle

> 4.2 V

0 V (SGND)

time

coa024

mode

100 ms

50 ms

modulated PWM

> 350 ms

2.2 V < V

mode

< 3 V

audio output

operating

standby

mute

50 %

duty cycle

> 4.2 V

0 V (SGND)

time

mode

100 ms

50 ms

modulated PWM

> 350 ms

Preliminary data sheet Rev. 01 — 1 October 2004 8 of 34

Philips Semiconductors

TDA8920B

2 × 100 W class-D power ampliﬁer

8.2 Pulse width modulation frequency

The output signal of the ampliﬁer is a PWM signal with a carrier frequency of

approximately317 kHz. Using a 2nd-order LC demodulation ﬁlter in theapplication results

in an analog audio signal across the loudspeaker. This switching frequency is ﬁxed by an

external resistor R

OSC

connected between pin OSC and V

SSA

. An optimal setting for the

carrier frequency is between 300 kHz and 350 kHz.

Using an external resistor of 30 kΩ on the OSC pin, the carrier frequency is set to

317 kHz.

If two or more class-D ampliﬁers are used in the same audio application, it is advisable to

have all devices operating at the same switching frequency by using an external clock

circuit.

8.3 Protections

The following protections are included in TDA8920B:

• OverTemperature Protection (OTP)

• OverCurrent Protection (OCP)

• Window Protection (WP)

• Supply voltage protections:

– UnderVoltage Protection (UVP)

– OverVoltage Protection (OVP)

– UnBalance Protection (UBP).

The reaction of the device on the different fault conditions differs per protection:

8.3.1 OverTemperature Protection (OTP)

If the junction temperature T

> 150 °C, then the power stage will shut-down immediately.

The power stage will start switching again if the temperature drops to approximately

130 °C, thus there is a hysteresis of approximately 20 °C.

8.3.2 OverCurrent Protection (OCP)

When the loudspeaker terminals are short-circuited or if one of the demodulated outputs

of the ampliﬁer is short-circuited to one of the supply lines, this will be detected by the

OverCurrent Protection (OCP). If the output current exceeds the maximum output current

of 8 A, this current will be limited by the ampliﬁer to 8 A while the ampliﬁer outputs remain

switching (the ampliﬁer is NOT shut-down completely).

The ampliﬁer can distinguish between an impedance drop of the loudspeaker and

low-ohmic short across the load. In the TDA8920B this impedance threshold (Z

)

depends on the supply voltage used.

When a short is made across the load causing the impedance to drop below the threshold

level (< Z

) then the ampliﬁer is switched off completely and after a time of 100 ms it will

try to restart again. If the short circuit condition is still present after this time this cycle will

be repeated. The average dissipation will be low because of this low duty cycle.

Preliminary data sheet Rev. 01 — 1 October 2004 9 of 34

Philips Semiconductors

TDA8920B

2 × 100 W class-D power ampliﬁer

In case of an impedance drop (e.g. due to dynamic behavior of the loudspeaker) the same

protection will be activated; the maximum output current is again limited to 8 A, but the

ampliﬁer will NOT switch-off completely (thus preventing audio holes from occurring).

Result will be a clipping output signal without any artefacts.

See also Section 13.6 for more information on this maximum output current limiting

feature.

Preliminary data sheet Rev. 01 — 1 October 2004 10 of 34

Philips Semiconductors

TDA8920B

2 × 100 W class-D power ampliﬁer

8.3.3 Window Protection (WP)

During the start-up sequence, when pin MODE is switched from standby to mute, the

conditions at the output terminals of the power stage are checked. In the event of a

short-circuit at one of the output terminals to V

or V

the start-up procedure is

interrupted and the system waits for open-circuit outputs. Because the test is done before

enabling the power stages, no large currents will ﬂow in the event of a short-circuit. This

system is called Window Protection (WP) and protects for short-circuits at both sides of

the output ﬁlter to both supply lines. When there is a short-circuit from the power PWM

output of the power stage to one of the supply lines (before the demodulation ﬁlter) it will

also be detected by the start-up safety test. Practical use of this test feature can be found

in detection of short-circuits on the printed-circuit board.

Remark: This test is operational during (every) start-up sequence at a transition between

Standby and Mute mode. However when the ampliﬁer is completely shut-down due to

activation of the OverCurrent Protection (OCP) because a short to one of the supply lines

is made, then during restart (after 100 ms) the window protection will be activated. As a

result the ampliﬁer will not start-up until the short to the supply lines is removed.

8.3.4 Supply voltage protections

If the supply voltage drops below ±12.5 V, the UnderVoltage Protection (UVP) circuit is

activated and the system will shut-down correctly. If the internal clock is used, this

switch-off will be silent and without pop noise. When the supply voltage rises above the

threshold level, the system is restarted again after 100 ms. If the supply voltage exceeds

±33 V the OverVoltage Protection (OVP) circuit is activated and the power stages will

shut-down. It is re-enabled as soon as the supply voltage drops below the threshold level.

So in this case no timer of 100 ms is started.

An additional UnBalance Protection (UBP) circuit compares the positive analog (V

DDA

)

and the negative analog (V

SSA

) supply voltages and is triggered if the voltage difference

between them exceeds a certain level. This level depends on the sum of both supply

voltages. An expression for the unbalanced threshold level is as follows:

th(ub)

≈ 0.15 × (V

DDA

SSA

When the supply voltage difference drops below the threshold level, the system is

restarted again after 100 ms.

Example: With a symmetrical supply of ±30 V, the protection circuit will be triggered if the

unbalance exceeds approximately 9 V; see also Section 13.7.

In Table 4 an overview is given of all protections and the effect on the output signal.

[1] Hysteresis of 20 degrees will inﬂuence restart timing depending on heatsink size.

Table 4: Overview protections TDA8920B

Protection name Complete shut-down Restart directly Restart every 100 ms

OTP Y Y

[1]

OCP N

[2]

WP Y

[3]

UVP Y N Y

OVPYYN

UBP Y N Y

Preliminary data sheet Rev. 01 — 1 October 2004 11 of 34

Philips Semiconductors

TDA8920B

2 × 100 W class-D power ampliﬁer

[2] Only complete shut-down of ampliﬁer if short-circuit impedance is below threshold of 1 Ω. In all other cases

current limiting: resulting in clipping output signal.

[3] Fault condition detected during (every) transition between standby-to-mute and during restart after

activation of OCP (short to one of the supply lines).

8.4 Differential audio inputs

Fora high common mode rejection ratio and a maximum of ﬂexibility in the application, the

audio inputs are fully differential. By connecting the inputs anti-parallel the phase of one of

the channels can be inverted, so that a load can be connected between the two output

ﬁlters. In this case the system operates as a mono BTL ampliﬁer and with the same

loudspeaker impedance an approximately four times higher output power can be

obtained.

The input conﬁguration for a mono BTL application is illustrated in Figure 6.

In the stereo single-ended conﬁguration it is also recommended to connect the two

differential inputs in anti-phase. This has advantages for the current handling of the power

supply at low signal frequencies.

9. Limiting values

[1] Current limiting concept. See also Section 13.6.

Fig 6. Input conﬁguration for mono BTL application.

IN1P

OUT1

power stage

mbl466

OUT2

SGND

IN1M

IN2P

IN2M

Table 5: Limiting values

In accordance with the Absolute Maximum Rating System (IEC 60134).

Symbol Parameter Conditions Min Max Unit

supply voltage - ±30 V

ORM

repetitive peak current in

output pin

maximum output

current limiting

[1]

8- A

stg

storage temperature −55 +150 °C

amb

ambient temperature −40 +85 °C

junction temperature - 150 °C

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