TB2934HQ Toshiba, TB2934HQ Datasheet - Page 3

• Manufacturer Part Number: TB2934HQ
• Manufacturer: Toshiba

Specifications of TB2934HQ

• No. Of Channels: 4
• Package: HZIP 25-P-1.00F
• Recommended Vcc (v): 13.2
• Rl=2 Ohm: 70W x 4
• Rl=4 Ohm: 43W x 4
• Rl=8 Ohm: -
• Features/built-in Functions: 4 BTL channels, internal standby/mute, BiCD process, power, I2C self-diagnosis, tweeter diagnostics, 34/26 dB gain
• Operating Voltage (v): 9 to 18

Caution and Application Information
channel.)
1. Voltage Gain Adjustment
2. Muting Time Constant and Pop Noise Suppression when V
Caution on the use of the muting function
software). However, this feature makes possible space and cost saving.
range is reduced as the output of Amp.1 is attenuated.
suppress the pop noise. The larger value capacitor is used,
the lower pop noise becomes but the longer the muting time
from the mute ON command sent to muting an output sound
actually. The charge period, which makes the delay of muting
after "Mute On" command is written, is MIN=30msec,
MAX=180msec in case of C4 (Pin 16) = 1 uF, Vcc=9 to 18V
and Tj = -40 to 150 degrees condition.
muting operates to eliminate the large pop noise basically.
enough in such a case, make this pin 16 set at low: 5 V and
less by external circuit for more effective to suppress the pop
noise.
low before going back to play mode.
“ON” or after turning stand by “off” by I
that it is necessary to send a “mute off” command to change from this condition to play mode.
function is determined by the value of C4, the designer should take into account the possible generation of
pop noise during switching operations. The pop noise which is generated when the power or muting
function is turned ON/OFF will vary according to the time constant set by capacitor C4 value.
time interval when the voltage on pin 16 is falling.
sent from µController while the voltage at pin 16 is rising.
If the effect of the internal low voltage muting is not
In this case, this pin 16 has to be released from setting at
Additionally, the initial state after turning the amplifier
The audio muting function is enabled when pin 16 is not set Low. While the time constant of the muting
However, the pop noise may become apparent as a “peaky” sound if the mute ON or OFF command is
This IC has no NF (negative feedback) Pins. Therefore, the voltage gain can not be adjusted (except by
The amplifier gain, G
Therefore, the total voltage gain is decided by expression below.
In the case when G
The capacitor C4 at pin 16 is for muting time constant to
As the V
In the case when C4 value is large and the time constant is long, pop noise will be suppressed during the
The voltage gain of amp.1: G
The voltage gain of amp.2A, B: G
The voltage gain of BTL connection: G
G
V
= G
CC
V1
is rapidly falling, the IC internal low voltage
+ G
V2
V
+ G
= 20dB selected via I
V
= 26dB, is calculated using the expression below:
V (BTL)
Input
Figure 1 Block Diagram
= 8 + 20 + 6 = 34dB
V1
= 8dB
V2
Amp. 1
2
= 20dB
C Bus is muted, so
(description is made referring only on the single
V (BTL)
2
C, G
3
V1
= 6dB
changed from 8dB to −6dB so that the output dynamic
Amp. 2A
Amp. 2B
Figure 2 Pin 16 MutingCircuit
16
CC
Rapidly Falls
From low oltage
muting circuit
TB2934HQ
To mute circuit
2006-06-14
(pin 16)