International Rectifier IRAUDAMP10 Bedienungsanleitung
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IRAUDAMP10 REV 1.1
IRAUDAMP10
300W x 2 Channel Class D Audio Power Amplifier
Using the IRS2052M and IRF6775
By
Jun Honda, Yasushi Nishimura and Liwei Zheng
CAUTION:
International Rectifier suggests the following guidelines for safe operation and handling of
IRAUDAMP10 Demo board;
Always wear safety glasses whenever operating Demo Board
Avoid personal contact with exposed metal surfaces when operating Demo Board
Turn off Demo Board when placing or removing measurement probes
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IRAUDAMP10 REV 1.1
TABLE OF CONTENTS PAGE
INTRODUCTION............................................................................................................................................... 3
SPECIFICATIONS ............................................................................................................................................ 3
CONNECTION SETUP ..................................................................................................................................... 5
CONNECTOR DESCRIPTION ......................................................................................................................... 5
TEST PROCEDURES....................................................................................................................................... 6
PERFORMANCE AND TEST GRAPHS .......................................................................................................... 7
SOFT CLIPPING............................................................................................................................................. 10
EFFICIENCY................................................................................................................................................... 11
THERMAL CONSIDERATIONS..................................................................................................................... 11
THERMAL INTERFACE MATERIAL’S PRESSURE CONTROL ................................................................................. 12
POWER SUPPLY REJECTION RATIO (PSRR)............................................................................................ 14
SHORT CIRCUIT PROTECTION RESPONSE .............................................................................................. 15
IRAUDAMP10 OVERVIEW ............................................................................................................................ 16
FUNCTIONAL DESCRIPTIONS..................................................................................................................... 18
IRS2052M GATE DRIVER IC ......................................................................................................................... 18
SELF-OSCILLATING FREQUENCY .................................................................................................................... 19
ADJUSTMENTS OF SELF-OSCILLATING FREQUENCY ......................................................................................... 19
INTERNAL CLOCK OSCILLATOR ....................................................................................................................... 19
SELECTABLE DEAD-TIME................................................................................................................................ 20
PROTECTION SYSTEM OVERVIEW ............................................................................................................ 21
CLICK AND POP NOISE REDUCTION ......................................................................................................... 23
BUS PUMPING............................................................................................................................................... 24
INPUT SIGNAL AND GAIN SETTING ........................................................................................................... 24
GAIN SETTING............................................................................................................................................... 25
IRAUDAMP10 FABRICATION MATERIALS................................................................................................. 27
IRAUDAMP10 PCB SPECIFICATIONS......................................................................................................... 31
REVISION CHANGES DESCRIPTIONS........................................................................................................ 34
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IRAUDAMP10 REV 1.1
Introduction
The IRAUDAMP10 Demo board is a reference design which uses only one IC (IRS2052M) to derive
appropriate input signals, amplify the audio input, and achieve a two-channel 280 W/ch (4Ω, THD+N=1%)
half-bridge Class D audio power amplifier. The reference design demonstrates how to use the IRS2052M
Class D audio controller and gate driver IC, implement protection circuits, and design an optimum PCB
layout using IRF6775 DirectFET MOSFETs. The reference design contains all the required housekeeping
power supplies for ease of use. The two-channel design is scalable, for power and number of channels.
Applications
AV receivers
Home theater systems
Mini component stereos
Powered speakers
Sub-woofers
Musical Instrument amplifiers
Automotive after market amplifiers
Features
Output Power: 300W x 2 channels (4Ω, THD+N=1%)
or 370W x 2 channels (4Ω, THD+N=10%)
Residual Noise: 220V, IHF-A weighted, AES-17 filter
Distortion: 0.008% THD+N @ 100W, 4Ω
Efficiency: 90% @ 300W, 4Ω, single-channel driven, Class D stage
Multiple Protection Features: Over-current protection (OCP), high side and low side
Over-voltage protection (OVP),
Under-voltage protection (UVP), high side and low side
Over-temperature protection (OTP)
PWM Modulator: Self-oscillating half-bridge topology with optional clock synchronization
Specifications
General Test Conditions (unless otherwise noted) Notes / Conditions
Supply Voltages ±50V
Load Impedance 4Ω
Self-Oscillating Frequency 500kHz No input signal, Adjustable
Gain Setting 30.8dB 1Vrms input yields rated power
Electrical Data Typical Notes / Conditions
IR Devices Used IRS2052M Audio Controller and Gate-Driver,
IRF6775 DirectFET MOSFETs
Modulator Self-oscillating, second order sigma-delta modulation, analog input
Power Supply Range ± 25V to ±50V Bipolar power supply
Output Power CH1-2: (1% THD+N) 300W 1kHz, ±50V
Output Power CH1-2: (10% THD+N) 370W 1kHz, ±50V
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IRAUDAMP10 REV 1.1
Rated Load Impedance 8-4ΩResistive load
Standby Supply Current +45/-95mA No input signal
Total Idle Power Consumption 7W No input signal
Channel Efficiency 90% Single-channel driven,
300W, Class D stage
.
Audio Performance Class D
Output
Notes / Conditions
THD+N, 1W
THD+N, 20W
THD+N, 100W
THD+N, 200W
0.015%
0.009%
0.008%
0.015%
1kHz, Single-channel driven
Dynamic Range 100dB A-weighted, AES-17 filter,
Single-channel operation
Residual Noise, 22Hz - 20kHzAES17 220
V
Self-oscillating – 500kHz
Damping Factor 51 1kHz, relative to 4Ωload
Channel Separation 74dB
74dB
70dB
100Hz
1kHz
10kHz
Frequency Response : 20Hz-20kHz
: 20Hz-35kHz
±1dB
±3dB 1W, 4Ω- 8ΩLoad
Physical Specifications
Dimensions 3.94”(L) x 2.83”(W) x 0.85”(H)
100 mm (L) x 72 mm (W) x 21.5 mm(H)
Weight 0.130kgm
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IRAUDAMP10 REV 1.1
Connection Setup
Fig 1 Typical Test Setup
Connector Description
Pin # Pin Name Pin Description
CN1
1 CH1 INPUT Analog input for CH1
2 GND Floating ground of Channel 1 input
3 GND Floating ground of Channel 2 input
4 CH2 INPUT Analog input for CH2
P1
1 -B -50V supply referenced to GND.
2 GND Ground signal from MB.
3 +B +50V supply referenced to GND.
P2 1 CH2 OUTPUT Output of Channel 2
2 GND Floating ground of Channel 2 output
P3 1 GND Floating ground of Channel 1 output
2 CH1 OUTPUT Output of Channel 1
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IRAUDAMP10 REV 1.1
Test Procedures
Test Setup:
1. Connect 4-200 W dummy loads to 2 output connectors (P2 and P3 as shown on Fig 1)
and an Audio Precision analyzer (AP).
2. Connect the Audio Signal Generator to CN1 for CH1~CH2 respectively (AP).
3. Set up the dual power supply with voltages of ±50V; current limit to 5A.
4. TURN OFF the dual power supply before connecting to On of the unit under test (UUT).
5. Connect the dual power supply to P1. as shown on Fig 1
Power up:
6. Turn ON the dual power supply. The ±B supplies must be applied and removed at the
same time.
7. One orange and two blue LED should turn ON immediately and stay ON
8. Quiescent current for the positive supply should be 45mA 10mA at +50V.
9. Quiescent current for the negative supply should be 95mA 10mA at –50V.
Switching Frequency test
10. With an Oscilloscope, monitor the switching waveform at test points VS1~VS2. Adjust
VR1A and VR1B to set the self oscillating frequency to 500 kHz 25 kHz when DUT in
free oscillating mode.
Functionality Audio Tests:
11. Set the signal generator to 1kHz, 20 mVRMS output.
12. Connect the audio signal generator to CN1(Input of CH1,CH2,CH3)
13. Sweep the audio signal voltage from 15 mVRMS to 1 VRMS.
14. Monitor the output signals at P2/P3 with an oscilloscope. The waveform must be a non
distorted sinusoidal signal.
15. Observe that a 1 VRMS input generates an output voltage of 34.88 VRMS(CH1/CH2). The
ratio, R4x/(R3x) and R30x/(R31x), determines the voltage gain of IRAUDAMP10.
Test Setup using Audio Precision (Ap):
16. Use an unbalanced-floating signal from the generator outputs.
17. Use balanced inputs taken across output terminals, P2 and P3.
18. Connect Ap frame ground to GND at terminal P1.
19. Select the AES-17 filter(pull-down menu) for all the testing except frequency response.
20. Use a signal voltage sweep range from 15 mVRMS to 1.5 VRMS.
21. Run Ap test programs for all subsequent tests as shown in Fig 2- Fig 7below.
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IRAUDAMP10 REV 1.1
Performance and test graphs
ColorS weep Trace Line S tyle Thick D ata Axis Com m ent
1 1 Blue Solid 2 Anlr.THD+N Ratio Left CH2
1 3 M agenta Solid 2 Anlr.THD+N Ratio Left CH1
0.001
10
0.002
0.005
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
%
100m 500200m 500m 1 2 5 10 20 50 100 200
W
±B Supply = ±50V, 4 ΩResistive Load
Fig 2 IRAUDAMP10, THD+N versus Power, Stereo, 4 Ω
.
ColorSweep Trace Line Style Thick Data Axis Comment
1 1 Blue Solid 2 Anlr.Level B Left CH2
1 2 Magenta Solid 2 Anlr.Level A Left CH1
-10
+4
-8
-6
-4
-2
+0
+2
d
B
r
A
20 200k50 100 200 500 1k 2k 5k 10k 20k 50k 100k
Hz
T
±B Supply = ±50V, 4 ΩResistive Load
Fig 3 IRAUDAMP10, Frequency response
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IRAUDAMP10 REV 1.1
Col orSweep Trace Line Style Thick Data Axis Comment
1 1 Green Solid 2 Anlr.THD+N Ratio Left 10W
2 1 Yellow Solid 2 Anlr.THD+N Ratio Left 50W
3 1 Red Solid 2 Anlr. THD+N Rat i o Left 100W
0.0001
100
0.001
0.01
0.1
1
10
%
20 20k50 100 200 500 1k 2k 5k 10k
Hz
Fig 4 THD+N Ratio vs. Frequency
ColorSweep Trace Line Style Thick Data Axis Comment
1 1 Blue Solid 2 Fft.Ch.1 Ampl Left CH2
1 2 Magenta Solid 2 Fft.Ch.2 Ampl Left CH1
-110
+0
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
d
B
V
10 20k20 50 100 200 500 1k 2k 5k 10k
Hz
Fig 5, 1V output Frequency Spectrum
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IRAUDAMP10 REV 1.1
ColorSweep Trace Line Style Thick Data Axis Comment
1 1 Blue Solid 2 Fft.Ch.1 Ampl Left CH2
1 2 Magenta Solid 2 Fft.Ch.2 Ampl Left CH1
-140
+20
-120
-100
-80
-60
-40
-20
+0
d
B
V
10 20k20 50 100 200 500 1k 2k 5k 10k
Hz
No signal, Self Oscillator @ 500kHz
Fig 6, IRAUDAMP10 Noise Floor
.
ColorSweep Trace Line Style Thick Data Axis Comment
1 1 Blue Solid 2 Anlr.Ampl Left CH2-CH1
1 2 Magenta Solid 2 Anlr.Ampl Left CH1-CH2
-100
+0
-90
-80
-70
-60
-50
-40
-30
-20
-10
d
B
r
A
20 20k50 100 200 500 1k 2k 5k 10k
Hz
Fig 7, Channel separation vs. frequency
.
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IRAUDAMP10 REV 1.1
Soft Clipping
IRS2052M has Clipping detection function, it monitors error voltage in COMP pin with a window
comparator and pull an open drain nmos referenced to GND. Threshold to detect is at 10% and
90% of VAA-VSS. Each channel has independent CLIP outputs. Once IRS2052M detects
Clipping, the CLIP pin can generate pulses to trigger soft clipping circuit, which can limit output’s
maximum power as Fig 9(soft clipping circuit is not available on AMP10 reference board).
R3A 1K
GND
C5A
10uF, 50V
Audio signal INPUT
S
G
D
Q6
MMBFJ112
R28A
1K
R29A
220KD3A
1N4148
C15A
10uF, 16V
Q5
DTA144EKA
R27A
3.3K
R5A
47K
R6A
47K
C6A
1uF,50V
R7A
470K
10uF,50V
C0A
Soft Clipping
CLIP Detection
IN-
VSS
GND
VAA
Fig 9 Soft Clipping Circuit
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