Power IC. TB2912HQ Datasheet
TOSHIBA Bi-CMOS Digital Integrated Circuit Silicon Monolithic
Maximum Power 41 W BTL × 4-ch Audio Power IC
The TB2912HQ is 4ch audio amplifier for car audio application.
This IC can generate high power, high quality sound output,
POUT MAX = 41 W, using a pure complementary P-ch and N-ch
DMOS output stage.
The built-in self diagnosis function which is included can be
controlled via I2C BUS.
In addition, stand-by and mute function, and various
Protection feature are included.
Weight: 7.7 g (typ.)
• High power output
: POUT MAX (1) = 41 W (typ.)
(VCC = 14.4 V, f = 1 kHz, JEITA max, RL = 4 Ω)
: POUT MAX (2) = 37 W (typ.)
(VCC = 13.7 V, f = 1 kHz, JEITA max, RL = 4 Ω)
: POUT MAX (3) = 70 W (typ.)
(VCC = 14.4 V, f = 1 kHz, JEITA max, RL = 2 Ω)
: POUT (1) = 27 W (typ.)
(VCC = 14.4 V, f = 1 kHz, THD = 10%, RL = 4 Ω)
: POUT (2) = 23 W (typ.)
(VCC = 13.2 V, f = 1 kHz, THD = 10%, RL = 4 Ω)
: POUT (3) = 46 W (typ.)
(VCC = 14.4 V, f = 1 kHz, THD = 10%, RL = 2 Ω)
• Low distortion ratio: THD = 0.015% (typ.)
(VCC = 13.2 V, f = 1 kHz, POUT = 5 W, RL = 4 Ω)
• Low noise: VNO = 90 µVrms (typ.)
(VCC = 13.2 V, Rg = 0 Ω, BW = 20 Hz to 20 kHz, RL = 4 Ω)
• Built in stand by & muting function: controlled via I2C Bus (pin 16)
• Built in clipping detection (pin 4)
• Built in I2C Bus for stand-by, mute, voltage gain control, self diagnosis: Output short detection, offset detection,
tweeter or speaker open detection (pin 22 and 25)
• Built-in various protection circuits (Note 1, Note 2)
Thermal shut down, over-voltage, out to GND, out to VCC, out to out short circuit
• Operating supply voltage: VCC (opr) = 9 to 18 V (RL = 4 Ω)
VCC (opr) = 9 to 16 V (RL = 2 Ω)
Note 1: Install the product correctly. Otherwise, it may result in break down, damage and/or degradation to the
product or equipment.
Note 2: These protection functions are intended to avoid some output short circuits or other abnormal conditions
temporarily. These protect functions do not warrant to prevent the IC from being damaged.
- In case of the product would be operated with exceeded guaranteed operating ranges, these protection
features may not operate and some output short circuits may result in the IC being damaged.
4 Clip Detection
7 Out1 (−)
23 Out4 (−)
Some of the functional blocks, circuits, or constants labels in the block diagram may have been omitted or
simplified for clarity.
Caution and Application Information (description is made referring only on the single
1. Voltage Gain Adjustment
This IC has no NF (negative feedback) Pins. Therefore, the voltage gain can not be adjusted (except by
software). However, this feature makes possible space and cost saving.
Figure 1 Block Diagram
The amplifier gain, GV = 26dB, is calculated using the expression below:
The voltage gain of amp.1: GV1 = 0dB
The voltage gain of amp.2A, B: GV2 = 20dB
The voltage gain of BTL connection: GV (BTL) = 6dB
Therefore, the total voltage gain is decided by expression below.
GV = GV1 + GV2 + GV (BTL) = 0 + 20 + 6 = 26dB
In the case when GV = 12dB selected via I2C, GV1 changed from 0dB to −14dB so that the output
dynamic range is reduced as the output of Amp.1 is attenuated.
2. Stand by and muting (pin 16)
The below procedure can make the pop noise suppress.
At turning on(Stand by off)
① I2C bus circuit awake as the pin 16 is 2.5V and more.
The voltage of pin 16 is pulled up to Vcc after this.
Therefore, the diode insertion is necessary between pin 16
and micro controller to stop the reverse current if the
micro controller control the pin 16 of this IC.
② Control the mute / standby function via I2C as I2C
command can be received after ① condition.
To mute circuit
From low voltage
To turning off (Standby on)
Figure 2 Stand by and Mute
① Control muting circuit to mute ON via I2C control or the pin 16 is set at M position
② Control the standby circuit to turn off via I2C bus and it become in standby mode after 53200 x C2(sec)
later from sending the standby ON command.
③ The pop noise generates if the pin 16 is set at L position in advance to the ②step, or from the ① step
to the ③ step directly.
The capacitor C4 at pin 16 is for muting time constant to 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..
As the VCC is rapidly falling, the IC internal low voltage muting operates to eliminate the large pop noise
Use the transistor which has the current capacitance more than 1mA to control the pin 16 in stable.