TDA7294HS STMicroelectronics, TDA7294HS Datasheet - Page 10

• Manufacturer Part Number: TDA7294HS
• Description: IC AMP AUDIO 100W AB MULTIWATT15
• Manufacturer: STMicroelectronics
• Type: Class ABr

Specifications of TDA7294HS

• Output Type: 1-Channel (Mono)
• Max Output Power X Channels @ Load: 100W x 1 @ 8 Ohm
• Voltage - Supply: ±10 V ~ 40 V
• Features: Depop, Mute, Short-Circuit and Thermal Protection, Standby
• Mounting Type: Through Hole
• Package / Case: Multiwatt-15 (Horizontal, Bent and Staggered Leads)
• Amplifier Class: AB
• No. Of Channels: 1
• Output Power: 100W
• Supply Voltage Range: ± 10V To ± 40V
• Thd + N: 0.005% @ 5W, 8ohm, VS=± 35V
• Load Impedance: 8ohm
• Operating Temperature Range: 0°C To +70°C
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-8882-5

TDA7294
APPLICATION INFORMATION
HIGH-EFFICIENCY
Constraints of implementing high power solutions
are the power dissipation and the size of the
power supply. These are both due to the low effi-
ciency of conventional AB class amplifier ap-
proaches.
Here below (figure 18) is described a circuit pro-
posal for a high efficiency amplifier which can be
adopted for both HI-FI and CAR-RADIO applica-
tions.
The TDA7294 is a monolithic MOS power ampli-
fier which can be operated at 80V supply voltage
(100V with no signal applied) while delivering out-
put currents up to 10 A.
This allows the use of this device as a very high
power amplifier (up to 180W as peak power with
T.H.D.=10 % and Rl = 4 Ohm); the only drawback
is the power dissipation, hardly manageable in
the above power range.
Figure 20 shows the power dissipation versus
output power curve for a class AB amplifier, com-
pared with a high efficiency one.
In order to dimension the heatsink (and the power
supply), a generally used average output power
value is one tenth of the maximum output power
at T.H.D.=10 %.
Figure 18: High Efficiency Application Circuit
10/17
+40V
+20V
GND
-20V
-40V
1000 F
1000 F
C1
C2
100nF
100nF
C3
C4
1000 F
1000 F
C5
C6
100nF
100nF
C7
C8
330nF
330nF
C10
C9
R1
R2
2
2
PLAY
ST-BY
1N4148
D5
IN
D1 BYW98100
D2 BYW98100
C11 330nF
C13 10 F
R14 30K
R13 20K
R15 10K
10 F
C14
R16
13K
From fig. 20, where the maximum power is
around 200 W, we get an average of 20 W, in this
condition, for a class AB amplifier the average
power dissipation is equal to 65 W.
The typical junction-to-case thermal resistance of
the TDA7294 is 1
avoid that, in worst case conditions, the chip tem-
perature exceedes 150
of the heatsink must be 0.038
bient temperature of 50
As the above value is pratically unreachable; a
high efficiency system is needed in those cases
where the continuous RMS output power is higher
than 50-60 W.
The TDA7294 was designed to work also in
higher efficiency way.
For this reason there are four power supply pins:
two intended for the signal part and two for the
power part.
T1 and T2 are two power transistors that only op-
erate when the output power reaches a certain
threshold (e.g. 20 W). If the output power in-
creases, these transistors are switched on during
the portion of the signal where more output volt-
age swing is needed, thus "bootstrapping" the
power supply pins (#13 and #15).
The current generators formed by T4, T7, zener
3
4
9
10
TDA7294
7
8
13
15
L1 1 H
L2 1 H
14
BDX53A
270
270
BDX54A
2
6
1
T1
T2
o
C/W (max= 1.5
R16
13K
22 F
C15
D3 1N4148
D4 1N4148
BC394
BC393
o
R3 680
o
C, the thermal resistance
T3
T6
C).
L3 5 H
270
C11 22 F
o
Z1 3.9V
Z2 3.9V
C/W (@ max am-
BC393
BC394
270
270
R4
T4
T7
R9
3.3K
3.3K
R7
R8
D93AU016
o
20K
R10
270
270
C/W). To
R5
R6
BC393
BC394
R11
29K
T5
T8
1.8nF
1.8nF
OUT
C16
C17