HCA250ACREF Data Sheet
October 1998
File Number
250W Class D Subwoofer Amplifier
Features
The HCA250ACREF Reference Design delivers 250WRMS power into a 2 Ω load with less than 0.1% THD. The amplifier will run continuously at rated power with no droop in output level. Since the efficiency is 90% at maximum power, no expensive, bulky heatsinks are required.
• 250 Watt Watt RMS Power Power (400 (400 Watt Watt Peak) Peak)
45 81
• Operation Operation from a Single Single Supply Supply • Meets FCC FCC Class Class B and CE Marking Marking Requir Requirements ements for EMC in a Typical Subwoofer Subwoofer Application • 10H 10Hz-2 z-20kH 0kHz z Bandwid Bandwidth th (3dB) (3dB) • 0.1% 0.1% THD THD (10Hz (10Hz to to 200Hz 200Hz)) • 90% Efficie Efficiency ncy at at Maximum Maximum Power Power
The design is par t of Intersil’s Cool Audio program that enabl ena bles es custom customers ers to achie achieve ve a minimu minimum m time-t time-to-ma o-marke rkett for for audio end products. products. The design is offered to Customers after execution of our Licensing Agreement, at which time, Intersil provides a documentation package containing 1) Circuit Description, 2) Schematics, 3) Test and Manufacturing Information, 4) A Bill of Materials with all vendor and vendor part numbers, 5) Intersil’s Engineering Support Contacts, 6) One Sample Amplifier Amplifier Board. For more information, see us on the web, home page http://www http: //www.int .intersil. ersil.com. com. For technical technical assistance, assistance, call Central Central Applications at 1-800-442-7747, or email us at
[email protected].
• Pop-F Pop-Free ree Start-U Start-Up p • Remo Remote te On/O On/Off ff • Soft Soft Clip Clippi ping ng • Thermal Thermal Protec Protectio tion n • Prot Protec ecti tion on for OUT OUT1 or OUT2 UT2 to GND GND Shor Shortt, and and OUT1 OUT1 to OUT2 Shorts
Applications • Subwoo Subwoofe ferr- and “Bi-”Ampl “Bi-”Amplifie ifiers rs
Ordering Information Contact Intersil Licensing Agents Continental Far East or International Operations. See contact information provided in this document.
Reference Design Block Diagram +15V
POWER AMPLIFIER
250W SUBWOOFER J1 PRE-AMPLIFIER
(J2)
+40V
HI PASS FILTER (>10Hz) AND ERROR AMPLIFIIER
+OUT
LOW PASS FILTER
-OUT
MODULATOR
OVER CURRENT THERMAL SHUTDOWN SOFT CLIPPING
J2 IS AN OPTIONAL AUDIO INPUT
4-1 4-1
LOW PASS FILTER
EN
GND
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. Coolaudio™ is a trademark of Intersil Corporation http://www http://www.inte .intersil.c rsil.com om or 407-727-9207 407-727-9207 | Copyright Copyright © Intersil Intersil Corporation Corporation 1999
HCA250ACREF Absolute Maximum Ratings
Operating Conditions
Supply Voltage, VBUS (Note 1) 1) . . . . . . . . . . . . . . . . . . . -0.3V to 50V 50V All Other Other Pin Voltage Voltages s (Note 1) 1) . . . . . . . VGND -0.3V to VBUS +0.3V
Supply Voltage, VBUS (Relative (Relative to GND). GND). . . . . . . . . . . +40V (+8, (+8, -4) Voltage on VSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0V Temperature Range (Amplifier (Amplifier Ambient) . . . . . . . . . . -40oC to 60oC
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTES: 1. All All volta oltage ges s are are rela relati tiv ve to VGND, unles unless s otherw otherwise ise specif specified ied..
Electrical Specifications
VBUS = 40V, RLOAD = 2.0Ω, VCOM = 0V TA = 25oC
PARAMETER
SYMBOL
TEST CONDITIONS
TYP
UNITS
SUPPLY MEASUREMENTS +15V Current Quiescent - Switching
VBIAS = 12V, EN = VBIAS
70
mA
+15V Current Quiescent - Non Switching
VBIAS = 12V, EN= VCOM = 0V
50
mA
Audio In = 0V, EN = V BIAS=15V
60
mA
170
µA
13.5
V
20
V
VBUS Quiescent Current
IBUS
REM On/OFF Quiescent Current (On)
REN
Minimum 15V Input Supply Voltage Maximum +15V Input Supply Voltage OUTPUT MEASUREMENTS (All In RMS) Maximum Output Power at 36V
PMAX
VBUS = 36V
2 50
W
Total Harmonic Distortion + Noise
THD+N
POUT = 150W, 100Hz
0 .1
%
SNR
VSNR
Relative to Full Scale Output, ≤ 5kHz
- 85
dB
PSRR (∆VOUT / ∆VBUS)
PSRR
VBUS = 40±10%
3
mV/V
-3dB (Note 2)
20
KHz
PERFORMANCE MEASUREMENTS
ADDITIONAL MEASUREMENTS Cutoff Frequency
FUPPER
PWM Frequency
FPWM
68
kHz
Amplifier Gain
AV
26
dB
Input Impedance
RIN
11.3
KΩ
NOTE: 2. See Figure 7, Frequency Frequency Response (Open and Closed Loop) Loop) Gain and Phase. Phase. 3. All measurements for this data data sheet taken on Audio Precision “System 2 Analyzer”.
Reference Board Connector Assignment SYMBOL
DESCRIPTION
EN
Remote on/off signal for the amplifier.
+40V
Amplifier output stage power source.
+OUT
The + polarity high power output.
-OUT
The -polarity high power output.
+15V
Logic supply voltage = 15VDC.
GND
Ground return for the amplifier.
SHLD
Shield connection for speaker cable.
J1
Audio input from preamp.
4-2 4-2
HCA250ACREF Typical Performance Curves
(VBUS = 40V, RLOAD = 2Ω, Except as noted otherwise)
2.0
2.0
1.0
1.0
0.5 ) % ( N + 0.2 D H T 0.1
0.5 ) % ( N +0.2 D H T 0.1
10W
0.05
300W - SOFT CLIPPING
250W - SOFT CLIPPING
0.05
150W
300W - NO SOFT CLIPPING
100W 0.02 20
30 40 50 60 80 10 100 200 300 400 500 600 7001k FREQUENCY (Hz)
FIGURE FIGURE 1. TOT TOTAL HAR HARMON MONIC IC DIS DISTO TORT RTION ION PLUS PLUS NOISE NOISE vs FREQUENCY AS A FUNCTION OF OUTPUT POWER
0.02 20
40
60
80 100
200
400
600 800 1k
FREQUENCY (Hz)
FIGURE FIGURE 2. TOT TOTAL HAR HARMON MONIC IC DIS DISTO TORT RTION ION PLUS PLUS NOISE NOISE vs FREQUENCY AS A FUNCTION OF OUTPUT POWER (WITH AND WITHOUT SOFT-CLIPPING) SOFT-CLIPPING)
2.0
2.0 10W, L2, L3 REMOVED
300W - SOFT CLIPPING 250W - SOFT CLIPPING
1.0
1.0
0.5 ) % ( N + 0.2 D H T 0.1
) % ( N + 0.2 D H T 0.1
0.5 100W, L2, L3 REMOVED 150W, L2, L3 REMOVED
300W - NO SOFT CLIPPING
250W - NO SOFT CLIPPING
0.05
0.05
0.02
250W - NO SOFT CLIPPING
20
50
100 200 FREQUENCY (Hz)
500
1k
FIGURE FIGURE 3. TOT TOTAL HAR HARMON MONIC IC DIS DISTO TORT RTION ION PLUS PLUS NOISE NOISE vs FREQUENCY AS A FUNCTION OF OUTPUT POWER (L2 AND L3 OUTPUT CHOKES REMOVED)
4-3 4-3
0.02 20
30 40 50 60 60 80 100 200 300 400 FREQUENCY (Hz)
600
1k
FIGUR FIGURE E 4. TOT TOTAL HA HARMO RMONICDIST NICDISTOR ORTIO TION N PLUS PLUS NOISE NOISE vs FREQUENCY AS A FUNCTION OF OUTPUT POWER POWER (L2 (L2 AN AND D L3 OUTPU OUTPUT T CH CHOK OKES ES REMO REMOVED FOR COST REDUCTION; WITH AND WITHOUT SOFT-CLIPPING)
HCA250ACREF Typical Performance Curves
(VBUS = 40V, RLOAD = 2Ω, Except as noted otherwise) (Continued)
100 95 90 ) % ( Y C N E I C I F F E
85 80 75 70 65 60 55 50 1
10
POUT (W)
100
10 3
FIGURE FIGURE 5. EFFICIENCY EFFICIENCY vs OUTPUT POWER POWER AT AT 100Hz
30 28 S26 M R24 , E22 G A20 T L O18 V T 16 U14 P T U12 O10 R E 8 I F I L 6 P M 4 A 2 0 500M
VBUS = 40V
392W
VBUS = 36V VBUS = 32V
8W
700M
900M 1.1 1.3 AUDIO INPUT VOLTAGE, RMS
4.5 ) B d ( 3.0 N I B A d 1.5 G 6 E 2 G O A T 0 T E L V O I V T-1.5 R A L E E I F R I L -3.0 P M A -4.5 100
1K FREQUENCY (Hz)
10K
30K
NOTE NOTE:: The The abov above e curv curve e show shows s the the freq freque uenc ncy y resp respon onse se from from 10Hz 10Hz to 20kH 20kHz z at 250W 250W outp output ut powe powerr. Note Note that the response is ±3dB from 10Hz -20kHz. FIGURE FIGURE 7. AMPLITUDE AMPLITUDE vs FREQUEN FREQUENCY CY
4-4 4-4
1.5
0W 1.7
FIGURE FIGURE 6. OUTPUT OUTPUT POWER POWER ANDVOLT ANDVOLTAGE vs AUDI UDIO O INP INPUT UT VOLTAGE VOLTAGE AS DC BUS VOLTAGE VOLTAGE IS VARIED
6.0
-6.0 10
) W ( , 288W Ω 2 O T 200W N I T U 128W P T U O 72W R E W 32W O P
HCA250ACREF Reference Board Physical Layout
4.35in. (110.5mm)
4-5 4-5
HCA250ACREF Evaluation Test Procedure HCA250ACREF Consumer Subwoofer Amplifier.
Equipment Test equipment required for proper evaluation of the 250W Intersil Subwoofer Amplifier are as follows: Two Regulated DC Power Supplies will be needed for testing. A high power supply with clean output and capable of supplying a constant 40V DC at 10A minimum continuously; and a lower voltage supply capable of providing 15V continuously at 100mA. A power supply with the current limit set to those specified above is recommended. For power supplies which do not read the current limit set-point directly, the position of the set point control corresponding to the appropriate current levels should be determined prior to starting the test and marked on the power supply control panel. Audio Audio Precisi Precision on System System 1 Analyz Analyzer er or equ equiv ivale alent, nt, capab capable le of providing clean audio input signals controllable in amplitude from 0V to 2.00V and frequencies from 10Hz to 20kHz. The system should also be capable of analyzing amplifier characteristics, Output Power, Frequency Response, Total Harmonic Distortion, and Noise. An output low pass filter may may be nee needed ded (altho (although ugh the Audio Audio Precis Precision ion Analyz Analyzers ers with with their Analyzer voltage scales set to 40 V will provide good results without a filter) to filter out the switching waveform waveform components resulting from class D amplification. This filter can be made from the schematic shown in Figure 9. The filter’s corner frequency is approximately 20kHz and is sufficient for verifying bandwidth. A 2Ω non-inductive resistive load capable of handling a minimum of 250W.
Procedure 1. Conn Connec ectt a shie shield lded ed cabl cable e betw betwee een n the the Audi Audio o Prec Precis isio ion n Analyzer signal output port and the RCA jack, J1, or the alte alterna rnati tive ve jack jack,, J2 on the the ampl amplifi ifier er.. Conn Connec ectt a #16A #16AWG WG twisted pair shielded cable between plug, JP1, and the 2.0Ω resistor set. Connect suitable wires between plug, JP2, on the amplifier and the 15V and 40V DC supplies using #16AWG twisted wire for GND and 40V DC and #22A #22AWG WG for for 15V 15VDC and and EN sign signal als s. Set Set the pin pin 2 to pin pin 3 volt voltag age e to 15V 15V and and the the pin pin 1 to 3 volta oltage ge to 40V 40V, bef before ore plugging in the JP2 plug into the am plifier board socket, JP2. JP2. Pres Preset et the the curr curren entt limi limitt sett settin ings gs of the the 15V 15V DC supply to 100mA and the bus supply curr ent to about 10A DC. 2. With With the the powe powerr supp suppli lies es off off, plug plug the the J1, J1, JP1 JP1 and and JP2 JP2 externa ternall conn connec ecto tors rs into into the the appr approp opria riate te ports ports on the the ampl ampliifier board. Make sure the board is sitting on a non conductive surface prior to powering up. The wire from the the remot remote e EN(a EN(abl ble) e) pin, pin, pin pin 4 (JP2 (JP2), ), shou should ld be disa disabl bled ed (not connected to +15V). 3. Withtheaud Withtheaudioinp ioinputsig utsigna nall set set at0mV, at0mV, turn turn onthe15V powpower supply supply follo followed wed by the 40V supply supply.. The indicat indicated ed current current from from the the 40V 40VDC supp supply ly shou should ld be zero zero and and for the the 15V 15VDC supp supply ly near near 50mA 50mA.. Next Next,, conn connec ectt the the EN wire wire to the the +15V +15V supply. The 15V DC supply current should increase to ap4-6 4-6
proxim proximat atel ely y 70m 70mA. A. The The 40VDC powe powerr supply supply curre current nt with with no input signal should be approximately 60mA. 4. If the the ampl amplif ifie ierr outp output ut is conn connec ecte ted d to a resi resist stiv ive e load load,, 2 Ω, 250W resistor, make sure the resistor is placed on a safe surface since it will get very hot during the evaluation test. 5. Depe Depend ndin ing g on the the type type of test testin ing g to be cond conduct ucted ed (Out (Outpu putt Power Power,, THDs THDs etc.) etc.) select selectthe themen menu u and contro controll pan panel el settin settings gs on the the Audi Audio o Prec Precis isio ion n Anal Analyz yzer er to cond conduc uctt the the test test.. Inpu Inputt frefrequen quency cy shou should ld be swep sweptt from from 10Hz 10Hz and and 1KHz 1KHz and and inpu inputt volt volt-age level should be increased slowly until desired output power is achieved. At 250W output power, the 40V DC bus bus power supply current should be approaching 8A. It is important tant to have have 40VD 40VDC C at the the JP2 JP2 plug plug in orde orderr to obta obtain in resu result lts s similar to those found in the data sheet. 6. Cond Conduc uctt the the desi desire red d test tests s in acco accord rdan ance ce with with the the Audi Audio o Precision test procedures. 7. Powerdown Powerdown aud audio io signal signal input input and pow power er suppli supplies es before before disconnecting the amplifier from the test set up.
Expected Test Results The Intersil 250W Subwoofer Amplifier is designed to provide 250W rms output power into 2 Ω speaker load with THD+N as shown shown in the the figur figures. es. As the amp amplif lifier ier output output powe powerr app approa roache ches s 250W, the output voltage swing approaches the limits of the supply supply volt voltage age (36V (36V min.) min.) and the output output wave wavefo form rm will will beg begin in to soft-clip, resulting in an increase in THD. Data sheet measurements were taken by measuring voltages at the JP1 and and JP2 JP2 pin pin by sold solderi ering ng smal smalll wire wire stub stubs s to the the conn connec ecto torr pins pins on the underside of the amplifier board. The onset of soft-clipping can be viewed by looking at test point TP2 with an oscilloscope probe with respect to a suitable ground on the amplifier board (the shield fence makes an excellent ground). A slight compression of the signal will occur as the input amplitude is increased further and further. Figure 2 shows results with and without softclipping at 250W and 300W. 300W. The effects of soft-clipping or comp compre ressi ssion on are are redu reduce ced d by a smal smalll incr increa ease se in bus bus volt voltag age. e. This is also evident from gain degradation of the amplifier with lowered bus voltage as shown in Figure 6. The short-circuit shutdown circuit can be tested by simply shorting the 2 Ω output resistors with a suitable means. Instantaneous disabling of the amplifier should be noticed. Also shorting either side of the load resistor to a suitable ground such as the shield fence will cause a similar shutdown. To To reset the amplifier, remove the shor t circuit and and then then eith either er the the +15V +15VDC supply supply potent potential ial or momenta momentaril rily y set the EN potential to GND.
HCA250ACREF Authorized Intersil Licensing Agents
.
HCA250ACREF
Asia 75Ω, 2W, 1% +OUT JP2
2Ω 250W 0.2µF, 1% NI LOAD
(NOTE 8)
-OUT
TO ANALYZER INPUT
75Ω, 2W, 1% POWER GROUND
NOTE: Use polypropylene polypropylene filter capacitors only. only. FIGURE 8. FILTER FILTER CIRCUIT FOR USE USE WITH AUDIO AUDIO PRECISION ANALYZER AND RESISTIVE LOADS
Continental Far East, Inc. 3-1-5 Azabudai, Minato-ku Tokyo 106, Japan Tel: 03-3584-0339 FAX: 03-3588-0930
North America And Europe International Operations, Inc. 15 Oakdale Manor Suffern, New York 10901 USA Tel: 914-369-3532 FAX: 914-369-1607
All Intersil semiconductor products are manufactured, assembled and tested under ISO9000 quality systems certification. Intersil semiconductor products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design and/or specifications at any time with- out notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see web site http://www.intersil.com
Sales Office Headquarters NORTH AMERICA Intersil Corporation P. O. Box 883, Mail Stop 53-204 Melbou Melbourne rne,, FL 329 32902 02 TEL: (407) 724-7000 724-7000 FAX: (407) 724-7240
4-7 4-7
EUROPE Intersil SA Mercure Center 100, Rue de la Fusee 1130 Brussels, Belgium TEL: (32) 2.724.2111 FAX: (32) 2.724.22.05
ASIA Intersil (Taiwan) Ltd. 7F-6, No. 101 Fu Hsing North Road Taipei, Taiwan Republic of China TEL: (886) 2 2716 9310 FAX: (886) 2 2715 3029
