LA4906 [SANYO]
17-W, 2-Channel BTL AF High-Efficiency Power Amplifier for Car Audio Systems; 17 -W ， 2通道BTL AF高效率功放汽车音响系统
| 型号： | LA4906 |
| 厂家： | 
SANYO SEMICON DEVICE |
| 描述： | 17-W, 2-Channel BTL AF High-Efficiency Power Amplifier for Car Audio Systems |
| 文件： | 总10页 (文件大小：364K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Ordering number : EN *5714
Monolithic Linear IC
LA4906
17-W, 2-Channel BTL AF High-Efficiency
Power Amplifier for Car Audio Systems
Preliminary
Overview
• Uses a single-voltage power supply from 8 to 18 V.
• Provides a full range of built-in protection circuits,
The LA4906 is a BTL two-channel power amplifier for
use in car audio systems. It uses a signal-following
switching technique in the power supply for the amplifier
output stage and a newly-developed nonlinear amplifier
that features nonlinear characteristics in the signal system.
These features hold increases in the number of external
components to a minimum, and reduce power dissipation
(and thus heat generation) in the practical operating region
to about 1/2 that of earlier class B amplifier ICs. This can
contribute significantly to miniaturization and weight
reduction in the heat sink and to reduction of the heat
generated within the end product case.
including shorting of output pin to V , shorting of
output pin to ground, overvoltage, and thermal
shutdown protection.
• Built-in standby switch
• Clipping detection function
CC
Package Dimensions
unit: mm
3160-SIP23HZ
[LA4906]
Features
• Power dissipation reduced by 50% (for music at average
power levels, as compared to earlier Sanyo products)
• The number of required signal-following switching
circuits has been reduced to just one circuit for two
channels, reducing the number of external components.
• The output is a pure analog signal; no switching noise
whatsoever appears on the output lines.
SANYO: SIP23HZ
Specifications
Absolute Maximum Ratings at Ta = 25°C
Parameter
Symbol
Conditions
Ratings
Unit
V
V
CC max1 With no signal, t = 1 minute
CC max2
18
16
Maximum supply voltage
V
V
Maximum output current
Allowable power dissipation
Operating temperature
Storage temperature
I
O Peak
Per channel
4.5
37.5
A
Pd max
Topr
With an arbitrarily large heat sink
W
°C
°C
–35 to +85
–40 to +150
Tstg
Notes: 1. Set VCC and RL to be in the range where Pd max does not exceed 37.5 W.
2. The overvoltage protection circuit operates at VCC = 26 V or higher.
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN
73097HA(OT) No. 5714-1/10
LA4906
Operating Conditions at Ta = 25°C
Parameter
Symbol
VCC
Conditions
Ratings
13.2
Unit
V
Recommended supply voltage
Allowable operating voltage range
Recommended load resistance
Recommended load resistance range
V
CC op
RL
8 to 16
4
V
Ω
RL op
2 to 4
Ω
Note: Set VCC and RL to be in the range where Pd max does not exceed 37.5 W.
Operating Characteristics at Ta = 25°C, VCC = 13.2 V, RL = 4 Ω, f = 1 kHz, RG = 600 Ω, in the recommended circuit
Ratings
Parameter
Quiescent current drain
Symbol
Conditions
Unit
min
80
typ
110
max
150
I
CC0
Ist
RL = ∞, VIN = 0
mA
µA
Standby current
0
30
10
32
Voltage gain
VG
V
O = 0 dBm
O = 1 W, LPF = 30 kHz
28
14
dB
Total harmonic distortion
THD
PO1
PO2
VNO
P
0.07
17
0.2
%
THD = 10 %, RL = 4 Ω
W
Output power
THD = 10 %, RL = 2 Ω
25
W
Output noise voltage
Ripple rejection ratio
Rg = 0, BPF = 20 Hz to 20 kHz
0.10
0.3
mVrms
Rg = 0, VCCR = 0 dBm,
BPF = 20 Hz to 20 kHz
SVRR
60
45
75
dB
dB
Rg = 10 kΩ, VO = 0 dBm,
BPF = 20 Hz to 20 kHz
Channel separation
CH sep
Ri
60
30
Input resistance
21
–200
3
39
+200
VCC
10
kΩ
mV
V
Output offset voltage
Standby on voltage
VN offset Rg = 0
VSTH
IDOFF
IDON
AMP = on, applied through a 10 kΩ resistor
Clipping detect off current
Clipping detect on current
THD = 1 %
1
µA
µA
THD = 10 %
100
150
200
With an arbitrarily large heat sink
Al heat sink, t = 1.5 mm
Tightening torque: 39 N·cm
With silicone grease applied.
2
Ambient temperature, Ta – °C
Heat sink area, Sf – cm
No. 5714-2/10
LA4906
Technologies for Increased Efficiency Used in the LA4906
• Signal-following switching technique
Regulator
output
The LA4906 uses a switching regulator for the power supply for the
amplifier output stage. The LA4906 significantly reduces power
dissipation by having the switching regulator output voltage follow
the signal. Also, the LA4906 restricts the number of switching
regulators required to just one circuit even though it implements a
BTL 2-channel amplifier by using the switching regulator in
combination with the nonlinear amplifier described below. (See
Figure 1.)
Nonlinear
amplifier
Amplifier
output
stage
Figure 1 Overview Block Diagram
• Nonlinear amplifier
The LA4906 adopts a nonlinear amplifier, which has the nonlinear
characteristics shown in Figure 2, in the signal system. The LA4906
dispenses with the lower side switching regulator by using a low 2 V
as the midpoint voltage instead of the 1/2 VCC used in normal
amplifiers.
This nonlinear amplifier is basically formed from a differential
amplifier that has a symmetrical negative feedback circuit. Although
the BTL output stage positive and reverse phase output waveforms
have a half-wave waveform that, when referenced to ground, is
expanded and compressed as shown in Figure 3, the combined
output waveform at the load terminals is identical to that of earlier
products.
Figure 2 Nonlinear Amplifier
Input/Output Characteristics
Regulator output (point C)
Loss in the output
transistor
RL = 4 Ω
Positive phase
output (point A)
Center point
Ground
f = 1 kHz
Rg = 600 Ω
With both channels
driven.
Calculated at Pd =
Regulator output (point C)
VCC × ICC – 2 P
O
Earlier SANYO
products (class
B amplifiers)
Reverse phase
output (point B)
Center point
Ground
High-efficiency
LA4906
Waveform between
the outputs
(Between A and B)
Output power, P – W
O
Figure 4
Figure 3 Output Waveforms
No. 5714-3/10
LA4906
Equivalent Circuit Block Diagram
Standby
switch
Standby switch
Switching
regulator
block
*
TR1
Ripple filter
Switch
driver
Switching transistor
2SD1668, class S
D1
SB40-05J
Flywheel diode
(Tokin Co. Ltd.)
(OS capacitor)
*
Amplifier output stage
Input amplifier
Nonlinear amplifier/output stage
4 to 2 Ω
Beep amplifier
Power supply/ground shorting
protection circuit
Overvoltage/thermal
protection circuit
* = Polyester film capacitors
Input amplifier
4 to 2 Ω
Nonlinear amplifier/output stage
Muting circuit used
at power on
Popping noise
prevention circuit
Pin Voltages (At V = 13.2 V, with 5 V applied to STBY through a 10 kΩ resistor, using a digital voltmeter)
CC
Pin No.
1
2
Pre - GND
0
3
4
5
6
7
8
C
Pin
IN2
1.36
IN1
1.36
BEEP
1.36
PWR - GND 1
0
–OUT1
2.03
+OUT1
2.03
Pin voltage (V)
13.0
Pin No.
9
C
10
11
12
SW OUT1
3.70
13
SW OUT2
3.70
14
15
SE B
4.0
16
SW - GND
0
Pin
VCC
13.2
VCC (SW)
13.2
SW E
3.73
Pin voltage (V)
3.92
Pin No.
17
18
19
20
21
STAND-BY
3.21
22
DDL OUT
0
23
Pin
+OUT2
2.03
–OUT2
2.03
PWR - GND2
0
D. C
12.1
ON-TIME
2.81
Pin voltage (V)
No. 5714-4/10
LA4906
Sample Printed Circuit Board
1. External component descriptions
C1 and C2
· Input capacitors. A value of 2.2 µF is recommended for these capacitors. Note that the low-frequency area
characteristics can be adjusted by changing f , which is determined by the values of C1 and C2. However, due to
L
impulse (pop) noise considerations, the value of C1 and C2 should not exceed 3.3 µF when C4 is 22 µF.
C3
· Beep amplifier input capacitor. A value the same as that of C1 and C2 is used. If the beep function is not used, connect
the beep input to PRE-GND through C3.
C4
· Set the amplifier turn-on time. A value of 22 µF is recommended. (This will result in a turn-on time of about 0.7
second.) The on time is proportional to the value of this capacitor, and any value may be used. However, due to
impulse (pop) noise considerations, a value of 22 µF or larger should be used.
C5, C6, C7, and C8
· Oscillation prevention capacitors. Polyester film (Mylar) capacitors with good temperature characteristics must be used.
(These are used together with R1, R2, R3, and R4.) We recommend values of 0.1 µF or higher for these capacitors
since the stability will differ somewhat depending on the printed circuit board layout actually used.
C9
· Decoupling capacitor (ripple filter)
C10
· Power-supply capacitor
C11
· Oscillation prevention capacitor for the switching regulator. A value of 1500 pF is recommended.
C12
· Switching regulator output smoothing capacitor. The LA4906 adopts a self-excited switching regulator technique. The
value of this capacitor must be optimized, since it influences both the self-excitation stability and the regulator
efficiency. We recommend using a 2.2-µF 25-V OS (Organic Semiconductor) capacitor with a low series resistance
and good temperature characteristics. Note that for the same reason a 2.2-Ω 1/2-W resistor should be used for the
associated resistor R6.
R5
· Standby switch current limiter resistor. A value of 10 kΩ is recommended. (When the voltage applied to the standby
switch is in the range 3 to 13.2 V.) Note that this resistor cannot be removed from this circuit.
No. 5714-5/10
LA4906
See the “Standby Function” section elsewhere in this document.
TR1
· External switching transistor. The 2SD1668 (rank S) is recommended.
If the application supports a load resistance RL of 4 Ω, a 2SD1667 (rank S) may be used. A heat sink must be provided
for this transistor, as well as for the IC itself.
D1
· Flywheel diode used to absorb energy from the coil. The SB40-05J, which is a Schottky barrier diode with a low VF, is
recommended.
If the application supports a load resistance RL of 4 Ω, an SB10-05A2 may be used. A heat sink must be provided for
this diode, as well as for the IC itself.
L1
· The Tokin Co., Ltd.-made HP-022Z [180 µH] (or the HP-011Z [200 µH] for 4-Ω applications) is recommended.
2. IC internal characteristics and other notes
Switching regulator
· The LA4906 includes a signal-following self-excited switching regulator to reduce power dissipation. The self-
excitation frequency with no input signal is about 100 kHz.
· To avoid spurious signal interference within the end product case, it is desirable to separate the tuner block from the
amplifier block by as far as possible. When designing the printed circuit board pattern, make the lines associated with
the switching regulator external components as short and as wide as possible.
· To prevent degradation of the LA4906 characteristics, separate the switching regulator external components from the
IC inputs (the input block pattern, the input capacitors, and the beep amplifier capacitor) by at least 1.5 cm.
Standby function
Pin 21 IC Internal Equivalent Circuit
500 µA or less
About 1.4 V (2VBE
)
· Pin 21 is the standby switching pin. The amplifier is turned on by applying
a voltage of over 3 V to pin 21 through an external resistor (R1).
· If the standby switch applied voltage will exceed 13.2 V, then the current
flowing into pin 5 must be held to under 500 µA. Use the following
formula to determine the value of R1 that meets this condition.
Applied standby
voltage
applied voltage – 1.4 V
R1 =
– 10 kΩ
500 µA
BEEP pin (pin 4)
· If the BEEP pin is used, use the smallest value of R102 (see figure)
possible (but note that this value must be under 100 Ω) to prevent
degradation of the IC's output noise voltage (V ) characteristics.
NO
Protection circuits
· The LA4906 includes an on-chip thermal protection circuit to prevent
destruction of or damage to the IC if abnormal heating occurs. If, due to
an inadequate heat sink or other reason, the IC junction temperature (Tj)
reaches or exceeds 160°C, the output is gradually attenuated by the
operation of the thermal protection circuit.
Beep signal
·
The overvoltage protection circuit operates if the V voltage exceeds 20 V.
CC
· While the LA4906 includes a power supply/ground short protection
circuit, it does not include a load shorting protection circuit. The idea
behind this design is that the thermal shutdown protection circuit will
protect the IC itself if the load is shorted. However, since a load short will
also cause temperature increases in the external transistor and coil, care is
required in handling this case.
Other notes
· Pin 22 is not connected electrically to any other points within the package.
No. 5714-6/10
LA4906
Both
channels
operating
Overvoltage
protection circuit
operation
Supply voltage, V –V
CC
Input level, V – mV rms
IN
Both
channels
operating
Both
channels
operating
Supply voltage, V –V
Supply voltage, V –V
CC
CC
Both
channels
operating
Both
channels
operating
Output power, P – W
Output power, P – W
O
O
Both
channels
operating
Input frequency, f – Hz
Input frequency, f – Hz
No. 5714-7/10
LA4906
Both
channels
operating
Input frequency, f – Hz
Input frequency, f – Hz
Using a 1-µF
power-supply
capacitor
Supply voltage, V –V
Input resistance, Rg – Ω
CC
Using a 1-µF
power-supply
capacitor
Using a 1-µF power-supply
capacitor
Calculate SVRR from the
following formula:SVRR = 20 log
(VO/VCCR)
Ripple frequency, f – Hz
Power supply ripple current voltage, V
– Vrms
R
CCR
Both
channels
operating
Both
channels
operating
Pd for the external
transistor
Output power, P – W
Output power, P – W
O
O
No. 5714-8/10
LA4906
Both
channels
operating
Both
channels
operating
Pd for the
external
transistor
Pd for the
external
transistor
Output power, P – W
Output power, P – W
O
O
(Tokin Co., Ltd.)
(OS capacitor)
In the recommended circuit
Supply voltage, V – V
CC
Ambient temperature, Ta – °C
Both
channels
operating
Both
channels
operating
Ambient temperature, Ta – °C
Ambient temperature, Ta – °C
With VST applied to pin 21 through a
10-kΩ resistor)
With VST applied to the standby pin
(pin 21) through a 10-kΩ resistor
· The time until the amplifier turns on
after V is applied
ST
Applied standby pin voltage, V – V
ST
No. 5714-9/10
LA4906
■ No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace
equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of
which may directly or indirectly cause injury, death or property loss.
■ Anyone purchasing any products described or contained herein for an above-mentioned use shall:
➀ Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and
distributors and all their officers and employees, jointly and severally, against any and all claims and litigation and all
damages, cost and expenses associated with such use:
➁ Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on
SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees
jointly or severally.
■ Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for
volume production. SANYO believes information herein is accurate and reliable, but no guarantees are made or implied
regarding its use or any infringements of intellectual property rights or other rights of third parties.
This catalog provides information as of July, 1997. Specifications and information herein are subject to change
without notice.
No. 5714-10/10
©2020 ICPDF网 联系我们和版权申明