LX1722HVEVALKIT - Microsemi Corporation

LX1722HV EVALUATION BOARD USER GUIDE

Microsemi Inc.

Integrated Products Division

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 1

Rev. 0.2, 2002-01-25

LXE1722HV AUDIOMAX

EVALUATION KIT

USER’S GUIDE

TM ®

LX1722HV EVALUATION BOARD USER GUIDE

Microsemi Inc.

Integrated Products Division

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 2

Rev. 0.2, 2002-01-25

LX1722HV Evaluation Board Quick Start Guide

LX1722HV EVB is a fully functional amplifier board for evaluation. It uses Microsemi’s LX1722, a stereo controller, to input

mono signal into both left and right channels with right channel polarity reversed. Then it takes both positive PWM outputs of left

and right channels leaving both negative outputs open into a pair of MOSFET drivers and MOSFETs, to level shift up to +VB

(48V in this EVB), to reach high power with BTL configuration. In this case, with zero input voltage, the duty cycle at each

output is around 50% and the signals are in-phase with each other, so there is basically no differential voltage across the speaker.

This topology will give you minimum quiescent current and no “pop” noise.

When the input signal goes positiv e, the duty cycle at OUT+ (left output) increases above 50% and the duty cycle at OUT- (right

output) decreases below 50% because the signal into right channel is reversed. This causes a net positive current to flow into the

speaker. A negative inpu t voltage causes the OUT- duty cycle to increase and the OUT+ duty cycle to decrease, which causes a

net negative current to flow into the speaker. The differential voltage across the speaker has a fundamental frequency of twice the

switching frequency. The speaker itself serves as the low pass filter, which then recreates the audio signal. This type of

modulation can be described as driving +VB, PGND and -VB across the speaker, which is why it is referred to as 3-Level

modulation.

The filter can be completely eliminated if the speaker is inductive at the switching frequency. The main trade off to eliminating

the filter is that the power from the switching waveform is dissipated in the speaker, which leads to a higher quiescent current,

IQQ. The speaker is both resistive and reactive, whereas an LC filter is almost purely reactive. The switching waveform, driven

directly into the speaker, may damage the speaker, however this is not as significant because the speaker cone movement is

proportional to 1/f2 for frequencies beyond the audio band. Therefore, the amount of cone movement at the switching frequency

is insignificant. But damage could occur to the speaker if the voice coil is not designed to handle the additional power.

Eliminating the filter also causes the amplifier to radiate EMI from the wires connecting the amplifier to the speaker. Therefore,

the filter less application is not recommended for EMI sensitive application s, or long speaker wire application.

The amplifier will support continuous output power levels up to > 200W into 6 ohm load (10% THD+N).

Board Setting

1. Power and Ground Connections: The terminal J6 is for the power supply connection. PVDD is connected to the

positive polarity of the power supply (+10V ~ +12V); the +VB is connected to the positive polarity of the power

supply (+48V); the GND is connected to the common negative polarity of this two power supplies. Please make

sure your power supp ly polarity connection and supply voltage is correct before you start to evaluate the board.

2. Speaker Connection: J4 is speaker output. Connect speaker “+” and “-“to “OUT+” and “OUT-“of J4. This

evaluation board is designed for 6 and 8 OHMS speaker load.

3. Audio Input Connections: J1 is the audio input conn ections for different input connecto rs. Both are different inputs,

but single-ended inpu t is available, just be careful, if the input audio source GND is not connected to the evaluation

board GND, close th e JUMPER JP1. When audio inpu ts are differential, the positive au dio inputs are connected to

IN+ pin, while the negative input is connected to IN- pin of the J1 header.

4. SLEEP/MUTE Connections: JP4 is the jumper selection for ON/OFF of the MUTE and SLEEP function. To enable

the amplifier, both jumpers should be set to “OFF” (SLEEP is OFF, default is left OPEN, and MUTE is OFF).

LX1722HV EVALUATION BOARD USER GUIDE

Microsemi Inc.

Integrated Products Division

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 3

Rev. 0.2, 2002-01-25

Audio Performance

1. 20Hz-20kHz Audio Bandwidth, less than ±1dB (8OHM);

2. Minimum THD+N <0.05% Typical (1KHz, 8 ohms);

3. Efficiency > 90%;

4. Output Power:

130W @8ohm, <1%THD+N ; 170W @8ohm, 10%THD+N

170W @6ohm, <1%THD+N ; 220W@6ohm, 10%THD+N;

5. Differential Input To Minimize noise Effects;

6. Tri-level modulation scheme To eliminate LC filter (certain conditions) and “PO P” noise;

7. Over current shut down and open load protection functions;

Absolute Maximum Ratings:

ABSOLUTE MAXIMUM RATINGS

Unless otherwise specified, the following specifications apply over the operating ambient temperature 0°C

≤

70°C

LX1722HV

Parameter Symbol Test Conditions Min Typ Max

Units

PVDD 10 12 15 V

Supply Voltage PVDD

+VB +VB 48 V

Sleep, PVDD = 12V -0.3 PVDD +

0.3 V

RPWM,CPWM, Mute PVDD = 12V -0.3 PVDD +

0.3 V

LIN+, LIN-, RIN+, RIN- VIN PVDD = 12V -0.3 PVDD

+0.3 V

Clock Frequency FOSC PVDD = 12V 150 300 450 KHz

LX1722HV EVALUATION BOARD USER GUIDE

Microsemi Inc.

Integrated Products Division

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 4

Rev. 0.2, 2002-01-25

AUDIO SYSTEM TEST

0.001

100

0.002

0.005

0.01

0.02

0.05

0.1

0.2

0.5

60m 500100m 200m 500m 1 2 5 10 20 50 100 200

PVDD=12V, VB=48V

Fin=1KHz,10~22KHz BPF

8OHM

6OHM

IGURE

–

THD+N

UTPUT

OWER

+30

+60

+32

+34

+36

+38

+40

+42

+44

+46

+48

+50

+52

+54

+56

+58

10 200k20 50 100 200 500 1k 2k 5k 10k 20k 50k

PVDD=12V, VB=48V

Vin=10mV,10~80KHz BPF

6OHM

8OHM

IGURE

–

REQUENCY

ESPONSE

LX1722HV EVALUATION BOARD USER GUIDE

Microsemi Inc.

Integrated Products Division

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 5

Rev. 0.2, 2002-01-25

AUDIO SYSTEM TEST (CONTINUED)

0.001

100

0.002

0.005

0.01

0.02

0.05

0.1

0.2

0.5

20 20k50 100 200 500 1k 2k 5k 10k

dx=-5.3228 kHz

PVDD=12V, VB=48V

RL=8OHM,10~22KHz BPF

100W

50W

10W

0.001

100

0.002

0.005

0.01

0.02

0.05

0.1

0.2

0.5

20 20k50 100 200 500 1k 2k 5k 10k

PVDD=12V, VB=48V

RL=6OHM,10~22KHz BPF

100W

50W

10W

IGURE

–

THD+N

REQUENCY

LX1722HV EVALUATION BOARD USER GUIDE

Microsemi Inc.

Integrated Products Division

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 6

Rev. 0.2, 2002-01-25

BILL OF MATERIALS

MISCELLANEOUS COMPONENTS

Line

Item Part Description Manufacturer & Part # Case Reference

Designators Qty

1 Microsemi IC Controller

ICROSEMI

LX1722 QSOP U1 1

2 MOSFET Driver IR IR2011 SO8 U2, U3 2

3 Diode 1N4148 D1, D2, D3, D7 4

4 24V ZENER Diode

ICROSEMI

1N5934 Powermite D8 1

5 Schottky Diode – option

ICROSEMI

CR1, CR2, CR3, CR4 4

6 22µH Inductor ABRACON L1, L2 2

7 2.2µH – option ISI L3, L4 2

8 MOSFET IR IRF530N TO-220 Q17 - Q20 4

9 Transistor – option 2N3906 SOT-23 Q21, Q22 2

10 N-MOSFET – option BSS138 SOT-23 Q5, Q23 2

11 Header 2x3 – option JP4 1

12 Header 2 – option J1, JP1 1

13 Terminal 2 – option J4 1

14 Terminal 3 – option J6 1

CAPACITORS

Line

Item Part Description Part Description Case Reference

Designators Qty

1 330µF, 100V C31, C35 2

2 0.1µF, 25V C2, C8, C29 3

3 0.47µF, 16V C3, C4, C5, C6 4

4 4.7µF, 16V Cxx 1

5 22pF C9, C11 2

6 100pF C7, C10, C12 3

7 4.7µF, 2%, Tantalum C17, C18 2

8 47µF, 25V C1, C14, C30 3

9 10nF, 25V -- option C39 1

10 1000µF, 100V C21 1

11 0.1µF, 100V C22, C32, C36 3

12 0.22µF C25,C26 2

13 0.22µF, 100V -- option C34,C38 2

14 1.0µF, 25V C19, C20 2

15 1.0µF, 50V C13 1

16 0.47µF, 100V C33, C37 2

17 4700pF C15, C16, C23, C24 4

18 1000pF – option C52 1

RESISTORS

Line

Item Part Description Part Description Case Reference

Designators Qty

1 4.99K, 1% 0805 RF1, RF2,RF3,RF4

R15,R17,R19,R21 8

2 10K, 5% 0805 R1, R3, R10, R11 4

3 56.2K, 1% 0805 R2, R4 2

4 49.9K, 1% -- R12 option 0805 R5, R12 2

5 1.37K, 1% -- option R13 1

6 10/1W 2512 R6, R7, R8, R9 4

8 0.030R, 1W 2512 R25 1

9 5.1k, 5% R23 1

10 1.00K, 1% R16, R18, R20, R22 4

12 82Ohm, 5% -- option R53 1

13 300K, 5% -- option R54 1

14 2.9K, 2W 5% -- option R55 1

15 100K, 5% -- option R56 1

16 500k, 5% -- option R14 1

17 20, 5% --option R105 1

LX1722HV

VALUATION

OARD

SER

UIDE

Microsemi Inc.

Integrated Products Division

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 7

Rev. 0.2, 2002-01-25

EVALUATION SCHEMATIC

Part

LFAOUT

CPWM

RPWM

_LMUTE

LEAOUT

LEAIN

VREF

CLOCK

GND

V25

LIN+

LIN-

LAMPOUT

RIN+

RIN-

RAMPOUT

SLEEP

STATUS

_RMUTE

REAIN

REAOUT

RFAOUT

LFBK

LFBK+

LISN

VDD

PVDD

PGND

LN+

LP+

LP-

LN-

RN-

RP-

RP+

RN+

PGND

PVDD

N.C.

RISN

RFBK+

RFBK

R1 10K

C7 100pF

R5 49.9K 1%

C10 100pF

R2 56.2K 1%

C9 22pF

MUTE

SLEEP

C13 1µF

50V

C8 0.1µF 25V

C3 0.47µF

C4 0.47µF

C5 0.47µF

C6 0.47µF

IN+

IN-

JP1

Jumper

C12 100pF

R4 56.2K 1%

C11 22pF

R3 10K GND PGND

FBCOM1

C18 4.7µF

25V TANT

C17 4.7µF

25V TANT

C19 1µF

25V

C20 1µF

25V

PVDD

Cxx

4.7µF

16V

R105 20

PVDD

Part

VDD

VSS

Part

VDD

VSS

D2 1N4148 C26

0.22µF

D1 1N4148 C25

0.22µF

R15 4.99K 1%

RF1

4.99K 1%

C15

4700pF

R16 1K 1%

R17 4.99K 1%

RF2 4.99K 1%

C16

4700pF R18 1K 1%

C29

0.1µF

25V

C30 47µF

25V

VCC

TP2 T POINT S

L2 22µH

C37

0.47µF

100V

L4 2.2µH

C38

0.22µF

100V

Q20

IRF530N

R9 10

Q19

IRF530N

C35 300µF

100V

C36

0.1µF

100V

R8 10

CR2

Option

GMSH

CR4

GMSH

L1 22µH

C33

0.47µF

100V

L3 2.2µH

C34

0.22µF

100V

Q18

IRF530N

R7 10

Q17

IRF530N

CR1

GMSH C31 300µF

100V

C32

0.1µF

100V

R6 10

CR3

Option

GMSH

TP1 T POINT S

R12

49.9K 1%

R13

1.37K 1%

D3 1N4148

C39 10nF

R14

500K

BSS138

C40C

SLEEP

OUT+

OUT-

FBCOM2

C21 1000µF

100V

C1 47µF 25

C22 0.1µF

100V

C2 0.1µF

25V

PVDD

D7 1N4148

VCC

R54 300K

R56 100K

C52

1000pF

Q23

BSS138

SLEEP

R53 10K

R25 0.030R 2W

FBCOM1

RF4 4.99K 1%

R21 4.99K 1% C24

4700pFR22 1K 1%

R20 1K 1%

R19 4.99K 1%

C23

4700pF

RF3 4.99K 1%

C14 47µF

25V

D8 24V

ZENER

R23 5.1K

R11 10K

PVDD

SLEEP MUTE

R10 10K

Sleep & Mute Jumpers

JP4

SLEEP

OFF

MUTE

OFF

U1 LX1722CDB

Error Amp

Clock

Differential Inputs

Error Amp

Over-Current

Protection

COM Feeback, ½ of V+ or 24V; RC LPF match the

Positive Feeback Phase

Feedback ½ (-6dB), 33KHz Cut-Off

Level Shift 12V -> 48 &

Half-Bridge FET Drivers

Feedback ½ (-6dB),

33KHz Cut-Off Half-Bridge

MOSEFT

Half-Bridge

MOSEFT

LC Filters, 2

Stage

OPTION

LC Filters, 2

Stage

OPTION

OUT-

OUT+

Over-Voltage Protection

IGURE

–

VALUATION

CHEMATIC