Lentini Benenati ABSTRACT LNBP integrated solution supplying/inte

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Lentini Benenati ABSTRACT LNBP integrated solution supplying/inte

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SUPPLY CONTROL VOLTAGE REGULATOR (PARALLEL INTERFACE)
Lentini Benenati
ABSTRACT LNBP integrated solution supplying/interfacing satellite modules. gives good performances simple economical way, with minimum external components. comprised functions that realize supplying/interfacing accordance international standards. INTRODUCTION. Figure Basic Satellite Installation
Parabola
Coaxial Cable Satellite Receiver
typical satellite receiver system formed these blocks (reported figure parabola antenna system focuses satellite signal LNB; (low noise block) placed focus parabola converts incoming signal 10GHz range lower frequency signal 1-2GHz range) called "first conversion signal". This allows signal carried inexpensive coaxial cable towards receiver. Additionally, improves first conversion signal level built-in noise amplifier. universal change type polarization (horizontal vertical) operative band command signals sent receiver; coaxial cable joins receiver carries functions: transfer first conversion signal from receiver; transfer command signals from receiver change polarization signal band; carry voltage supply LNB. receiver converts first conversion signal into control signals system. receiver provides that provides important features:
July 2000
1/17
AN1230 APPLICATION NOTE supply block; generate signals/voltages that needs operate correctly. supply/interface block placed inside receiver. must perform following functions: ready accept future digital standards with external modulation input fast oscillator start-up; implement loop-through function slave condition single dish, multiple receiver system; accept paralleling more receivers and, this condition. avoid flow reverse current from output GND; give accurate, thermal compensated outputs with possibility compensate voltage drop caused long coaxial cables; reliable; provide overload (better dynamic) thermal protection with diagnostic; avoid every type trimming; provide possibility driven microcontroller simple digital logic implement these functions; Finally, must cheap small area board. these functions hard implemented with discrete components, greatly made easier using integrated device, like LNBP, that been specially designed this purpose. FUNCTIONAL BLOCKS. LNBP comprises following operative blocks (see figure Figure Internal Block Diagram
Vcc1 Vcc2
.AMP.
CILLAT 22KHz
VOLT
.AMP.
LINE NGHT COMPE
LIMIT
PORT
PROT.
2/17
AN1230 APPLICATION NOTE oscillator activated putting (Enable Tone) factory trimmed 22KHz 2KHz, avoiding need external trimming. rise fall edges controlled 15µs range, 10µs typ., avoid pollution towards receiver. Duty Cycle typ. modulates output with 0.3V amplitude average. presence this signal usually gives information about band received. OSEL (OUTPUT PORT SELECTION) selects outputs (LNBA LNBB), order drive dual-dish system, depending present state. When OSEL LNBA port selected. When OSEL LNBB port selected. LNBA LNBB outputs supply either 18V. VSEL (VSEL selected, otherwise, VSEL high (VSEL selected. This kind feature changes LNBP polarization type. switches horizontal vertical polarization depending supply voltage gets from receiver. order keep power dissipation device low, input selector automatically selects Vcc1, that lowest input voltage, when selected (i.e. VSEL selected (i.e. VSEL Vcc2 input selected. power dissipation Iout=500mA Pd=(22-18)*0.5=2W (with Vcc2=22V Vout=18V) (15-13)*0.5=1W (with Vcc1=15V Vout=13V). Without input selection should have Pd=(22-13)*0.5=4.5W, which much higher. Moreover, internal switch selects (MASTER INPUT) transferred LNBA when low. This case occurs when receivers connected series slave receiver (the nearest antenna) disabled. master receiver supplies means input slave receiver. line length compensation function useful when antenna connected receiver long coaxial cable that adds considerable voltage drop. When output voltage selected increased about reference drives internal blocks that require high precision thermal compensated voltage source. LNBP different protection features, both turn outputs. first acts overload conditions (i.e. output current 500mA), second overheating (i.e. Tamb 150°C). overload protection case occurs when output current request 500mA. this condition device limits output current 500mA time depending Cext value. When elapsed, output goes time Toff=15*Ton. This keeps power dissipated device overload conditions, avoids oversize heatsink such condition. thermal protection case output disabled until chip temperature fallen. After that LNBP restarts working properly. LNBA bypass switch protected, input must driven current limited voltage source. Figure LNBP Grouping
LNBA LNBB
INPUTS
Vcc2 Vcc1 LNBP20CR
OUTPUTS
CONTROL SIGNAL
(ACTIVE (ACTIVE (ACTIVE OSEL (L=LNBA, H=LNBB) VSEL (L=13V, H=18V)
EXCEXT
3/17
AN1230 APPLICATION NOTE figure LNBP pins grouped functions. control signals logic inputs that control function, recommended that exceed Cext controls restore timing overload protection. overload protection present, output goes time imposed Cext value. same time pin, open collector output, goes low. figure figure behavior Toff times Cext respectively shown. When Toff elapsed, output returns active time Ton=Toff/15. Then, returns high impedance output. overload still present cycle repeated. This behavior greatly reduces dissipation device. fact, short circuit conditions with Vcc2=25 considering Iout internally limited 650mA Toff=15*Ton obtain: that lower than power dissipated normal conditions. Figure Overload Protection Time versus Cext
time Cext
(ms)
CAPACIT Cext
Figure Overload Protection Time versus Cext
time Cext
5,000 4,000
toff
3,000
2,000 1,000
CAPACIT Cext
Cext must properly chosen. related Iout Cout (total capacitor connected LNBA LNBB output) values. Large Cout values start-up give high current peak long time, consequently, overload condition time that could greater than imposed Cext. output will forced low, completely discharge will start. proper necessary that
4/17
AN1230 APPLICATION NOTE Cout/Cext also gives information about thermal protection status. thermal protection triggered, output disabled goes low. When chip temperature fallen, output returns active returns 3-state condition. sensing ON/OFF ratio signal, microcontroller discriminate overload thermal protection present. EXmodulates Vout capacitor connected series (see figure this case: Vout a.c.=Vin a.c.*Vout d.c./3 where, respectively, Vout a.c. a.c. alternate components Vout Vin, Vout d.c. direct component Vout. example, a.c. signal 600mV p.p. must imposed d.c. out, formula follows: a.c.= 3*Vout a.c./Vout d.c.=3*600/13 p.p. dispose 0-5V square wave signal modulate output voltage, necessary lower this signal amplitude. accordance figure have: R1=R2*(V1/Vin-1). Figure EXInput
External Modulation EXCin 10µF Input
LNBA LNBB
Vout
LNBP
Figure Adjust External Modulation Level
External 10µF EXModulation LNBA Input
LNBB
Vout
LNBP
must 50Ohm range minimize effects EXinput resistance variations. example obtain: R1=50*(5/0.14-1)=1.7kOhm. side effect, EXmodifies Vout resistor connected between this input GND. Figure report Vout value
5/17
AN1230 APPLICATION NOTE Figure Vout Value Resistance EXpin VSEL
Vout value Resistance
15.00
14.50
OUTPUT VOLTAGE
Vcc1= Vcc2
14.00
13.50
13.00
Ta=+25°C
12.50
12.00
4.7K 2.2K 1.5K
Resistance (Ohm)
Figure Vout Value Resistance EXpin VSEL
Vout value Resistance
20.50
OUTPUT VOLTAGE
20.00
Vcc1= Vcc2
19.50
19.00
18.50
Ta=+25°C
18.00
17.50
4.7K 2.2K 1.5K
Resistance (Ohm)
Figure LNBP Output Stages
Vcc2
LNBA
LNBB
Vcc1
6/17
AN1230 APPLICATION NOTE OPERATING MODE. LNBP power inputs (Vcc1, Vcc2 outputs (LNBA, LNBB) internally connected accordance scheme reported figure analyzing this scheme make following results: N-channel Power MOSFET with source connected LNBA. driven SW1, that joins gate Vcc2. drop between LNBA TR1, some conditions increased inadequate driving. fact have: that drop minimized increasing (Vcc2-VMI) value. example, Vcc2 increases, effect inadequate driving cancelled. depends Iout characteristics. Figure gives Iout plot, with Vcc2-VMI parameter. Therefore, given Iout,Vcc2 calculate Vdrop. Vcc2=22V, MI=21V Iout=500mA formula follows: Vdrop=Vgs-1V. figure results that Vgs=3.1V ILOAD=500mA Vcc2-VMI=1V such conditions Vdrop=3.1V-1V=2.1V. increase Vcc2 obtain: Vdrop=5.65V-5V=0.65V, which much lower. Figure Loop-Through Switch Gate Voltage
igure
Vcc2 -VMI
Iout
Vcc2 -VMI
Vcc2 -VMI
Vcc2
Iout (mA)
some cases happens that more receivers share same coaxial cable making their output hard paralleled, same voltage present outputs receivers. receiver disconnected mains, will flow current from LNBA means parasitic diode. Moreover, TR4) BVb-e could exceeded, reverse current could flow from LNBA Vcc2 Vcc1) from LNBB Vcc2 Vcc1), with possible destruction relative transistor. overcome this drawback enough diodes, depending many outputs used, series LNBA LNBB pins (see figure 12). this case have consider voltage drop across diode that load temperature dependent. These effects minimized using Schottky diodes activating function. alternative one, three diodes depends one, three inputs used series input oins Vcc1 Vcc2 (see figure 13). this case diodes causea change Vout, only worsening voltage drop, that minimized using Shottky diodes. Diodes used figures must withstand continuous current almost breakdown voltage (suggested type BYV10-30).
7/17
AN1230 APPLICATION NOTE Figure Reverse Current Protection Using Diodes Outputs
Vcc2 Vcc1
LNBA
LNBA' LNBB'
LNBP
LNBB
Figure Reverse Current Protection Using Diodes Inputs
Vcc2' Vcc1'
LNBA Vcc2
LNBP
LNBB
Vcc1
alternative one, three diodes, depending many inputs used, series Vcc1 Vcc2 input pins (see figure 13). this case diodes cause change Vout, only worsen voltage drop, which minimized using Schottky diodes. Diodes used figures must withstand continuos current almost breakdown voltage (suggested type BYV10-30). APPLICATION HINTS. LNBP compensate voltage drop across cable. This adds discrete value selected output voltage when active. also possible obtain continuous variation LNBA LNBB voltage using EXinput. only single source suitable, cost higher power losses device higher heatsink surface, possible power Vcc1 Vcc2 pins same source without affecting other circuit performance. order reduce power dissipation device, useful insert adequate resistor series Vcc1 (see figure14). This resistor must dimensioned considering that minimum voltage Vcc1 must with supply current ISUPPLY This means: (22-16) Ohm. Power dissipated this resistor R*Iout2 (500*10 -3)2 recommended bypass Vcc1 Vcc2 pins 2.2µF electrolytic capacitors. power dissipated saved device. Vcc2 inserted (i.e. receiver connected mains) bypass LNBA, because gate driven (see figure 10). possible overcome this drawback using scheme reported figure
8/17
AN1230 APPLICATION NOTE Figure Vcc1 Using Drop Resistor
LNBA
VCC2
LNBP
LNBB
VCC1
Figure Loop-Through Switch That Works Without Vcc2
VCC2
LNBP
VCC1
SINGLE SUPPLY APPLICATION. some applications receivers, cards, etc.) power supply available. possible this voltage supply LNBP. Figure reports schematic application proposed. uses MC34063 step-up input value 23V, depending Vsel status. Vsel (i.e. LNBP gives LNBA), voltage available point Vsel (i.e. LNBP gives LNBA), voltage available point This keeps power dissipated LNBP gives good efficiency because LNBP supplied with minimum drop. Diode protects LNBP reverse current. LNBP disabled (i.e. voltage selected point regardless Vsel status. changing voltage point actuated HC03, which open-drain quad 2-input nand gate. Figure Single Supply Application Using MC34063A Plus LNBPxx
150uH +Vin 0R15 0.5W
BYV10-40 2.7K
100R
330uF
HC03
1N4007 LNBA 13/18 10nF BYV10-40 VSel
.22uF
Vcc1 LNBA Vcc2 4.7uF Cext VSel
HC03
HC03
100uF
MC34063
1.2K
LNBP
9/17
AN1230 APPLICATION NOTE DiSEqC* SPECIFICATION. Figure Impedance Matching DiSEqC
LNBP
LNBA LNBB
270µH
DiSEqC
DiSEqC standard born implement most complex system required, example, multiple-satellite installations, where multiple placed parabola must communicate with receiver two-way mode. This standard compatible with 13/18V 22kHz tone easily implemented microcontroller. requires hardware specifications that faithfully satisfied LNBP. particular, impedance matched using scheme reported figure THERMAL MANAGEMENT. Figure Thermal Resistance versus On-Board Copper Heatsink Area
LNBP built-in dynamic protection system that considerably lowers power dissipation short overload conditions. Therefore, operative condition worst condition power dissipation. LNBP available packages: PowerSO-10, PowerSO-20 MULTIWATT15. last package assembled heatsink with: heatsink (Tj-Tamb)/Pd Thjc Thcs, where: Tj=junction temperature (can fixed 150°C max); Pd=dissipated power= (Vin-Vout)*Iout; Thjc junction-case thermal resistance ~2°C/W;
10/17
AN1230 APPLICATION NOTE Thcs =case-heatsink thermal resistance ~1÷1.5°C/W. packages must obtain right Thtot. This achieved soldering metallic case package adequate copper surface that acts like heatsink. figure typical Thtot heatsink Thjc Thcs copper surface shown, board with layers. layers case, convenient number ways (~9/cmsq) must provided. best results these ways must inserted below device near Doubling surface obtain 3°C/W reduction. Figure Electrical Schematic Board PowerSO-20BYV10-40
BYV10-40
VCC1
2.2µF
VCC1 LNBA
BYV10-40 2.2µF
220nF
LNBP20PD
220nF
VCC2
VCC2
10nF
GREEN 2.2K
LNBA
EX
10µF 470Ohm
EXENT OSEL VSEL
LNBB
GREEN 2.2K
LNBB
10nF
CEXT
4.7µF
Figure Electrical Schematic Demoboard MULTIWATT15BYV10-40
BYV10-40
VCC1
2.2µF
VCC1 LNBA
Probe
LNBA-S LNBA-F
BYV10-40 2.2µF
220nF
LNBP20CR
VCC2
VCC2
10nF
GREEN 2.2K
Probe
EX
LNBB-S
GREEN 2.2K
10µF
EXENT OSEL VSEL
LNBB
LNBB
10nF CEXT 4.7µF
Overload
470Ohm
GND-S GND-F
11/17
AN1230 APPLICATION NOTE Figure PowerSO-20 Demoboard
Figure MULTIWATT15 Demoboard
12/17
AN1230 APPLICATION NOTE
demoboards LNBP PowerSO-20 MULTIWATT packages shown below. different layer drawings shown figure first based PowerSO-20 package second MULTIWATT packages. SCHEMATIC CIRCUIT DESCRIPTION. 10.1 POWER SO-20Package. comb connectors pins each) used input output voltage control signals (Vsel, Osel, LLC, ENT). possible force high levels control signals through dip-switch. control signals come from outside board, dip-switches must position. oscilloscope probe connected test points monitor 22KHz signal. 10.2 MULTIWATTPackage. MULTIWATT electric schematics shown figure board some plugs provided input following signals: Vcc1,Vcc2, (force sense). Also, LNBA LNBB (force sense) connected plugs. load connected between output connector LNBA-F LNBB-F) GND-F. Between LNBA-S LNBB-S) GND-S voltmeters connected monitor output voltage. Besides, plugs connected with outputs permit insertion oscilloscope probes monitor 22kHz tone. EXinput connected relative connector. moreover, possible force high level following inputs: Osel, ENT, Vsel, five switches. moreover possible force such inputs even through five poles connector. this case switches must position. CONCLUSION This paper gives practical information develop numerous applications using this solution supplying satellite LNB. existing LNBP Demoboard allows development final product. next pages there numerous examples typical application schematics based LNBP. Typical Application Schematics shown below. Figure Antenna Ports Receiver
MCU+V
CONNECTORS VCC1 VCC2 LNBA LNBB CEXT 4.7µF
DATA
10uF EXR1
VSEL OSEL
TUNER
0.1µF 47nF
LNBP20CR
I/Os
I/Os
SUPPLY CONTROL VOLTAGE REGULATOR (DOUBLE DISH)
13/17
AN1230 APPLICATION NOTE Figure Single Antenna Receiver with Master Receiver Port
MCU+V
DATA
10uF EXR1
VSEL OSEL
VCC1 VCC2 LNBA LNBB CEXT
MASTER
4.7µF
TUNER
47nF 0.1µF
LNBP20CR
I/Os
I/Os
SUPPLY CONTROL VOLTAGE REGULATOR (SINGLE LNB)
Figure Using Serial Save I/Os
MCU+V DATA 10uF
EXVCC1 VCC2 LNBA LNBB CEXT 4.7µF
CONNECTORS
VSEL OSEL
TUNER
0.1µF 47nF
LNBP20CR
4094 MCU+V I/Os
SERIAL
SUPPLY CONTROL VOLTAGE REGULATOR (DOUBLE LNB)
14/17
AN1230 APPLICATION NOTE Typical Schematics cont'd Figure Antenna Ports Receiver
VCC1 VCC2 LNBA LNBB
CONNECTORS
Cost Solution Using PowerSO-10
VSEL CEXT 4.7µF OSEL
0.1µF 47nF
TUNER
MCU+V
LNBP10SP
I/Os
I/Os
SUPPLY CONTROL VOLTAGE REGULATOR (DOUBLE LNB)
Figure Connecting Together Vcc1 Vcc2
VCC1 VCC2 LNBA LNBB
4.7µF 0.1µF 47nF
CONNECTORS
VSEL CEXT OSEL LNBP10SP
TUNER
MCU+V
I/Os
I/Os
SUPPLY CONTROL VOLTAGE REGULATOR (DOUBLE LNB)
15/17
AN1230 APPLICATION NOTE Figure Single Antenna Receiver with Master Port
Using PowerSO-10
EXVCC1 10µF VCC2 LNBA VSEL CEXT 4.7µF Cost Solution DATA
TUNER
MASTER
MCU+V LNBP13SP
47nF
0.1µF
I/Os
I/Os
SUPPLY CONTROL VOLTAGE REGULATOR (SINGLE LNB)
Figure Single Antenna Receiver Overload Diagnostic
MCU+V
DATA
10µF
EX10 VSEL
VCC1 VCC2 LNBA 4.7µF 47nF 0.1µF
CEXT
TUNER
Cost Solution Using PowerSO-10
LNBP15SP
I/Os
I/Os
SUPPLY CONTROL VOLTAGE REGULATOR (SINGLE LNB)
16/17
AN1230 APPLICATION NOTE
Information furnished believed accurate reliable. However, STMicroelectronics assumes responsibility consequences such information infringement patents other rights third parties which result from use. license granted implication otherwise under patent patent rights STMicroelectronics. Specification mentioned this publication subject change without notice. This publication supersedes replaces information previously supplied. STMicroelectronics products authorized critical components life support devices systems without express written approval STMicroelectronics. logo registered trademark STMicroelectronics 2000 STMicroelectronics Printed Italy rights reserved
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Lentini Benenati ABSTRACT LNBP integrated solution supplying/inte

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