Texas Instruments LP8862-Q1EVM Скачать руководство пользователя страница 8 | Manualshive

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Texas Instruments LP8862-Q1EVM Скачать руководство пользователя страница 8

Start-Up of the EVM and Power Sequences

6

Start-Up of the EVM and Power Sequences

The LP8862-Q1 EVM is set up for easy start-up:

•

Connect LEDs to OUT1 and OUT2 of connector J16. (Note: LED current default is 160 mA and boost
voltage default is 37 V. LED outputs that are not used must be grounded via jumpers J11 orJ12.)

•

Connect input (BATTERY) voltage 12V to connector J25.

The LEDs turn on immediately because the jumpers on the EVM are set up for PWM input of 100% duty
cycle. For connector and jumper positions, see

and

.

Input (BATTERY) voltage range is 4.5 V to 40 V.

The LP8862-Q1 has a dual function VDDIO/EN pin. By default, VDDIO/EN = 3.3V is generated
automatically on the EVM from battery input voltage, via jumpers J1 and J26. VDDIO/EN acts as enable
for the chip as well as supply/reference voltage for IO logic. Device starts when V

IN

voltage is present and

above the V

IN

UVLO voltage level (4 V), and the VDDIO/EN voltage is set above threshold voltage (1.2 V).

By default, boost switching frequency is 400 kHz (jumper J4 connecting R3 = 160 k

Ω

to FSET) and boost

maximum voltage is 37 V (R12 = 750 k

Ω

and R13 = 130 k

Ω

). See

and

for

descriptions of how to change boost settings.

By default, LED current is 160 mA per string (jumper J5 connecting R4= 30 k

Ω

to ISET). See

for descriptions of how to change LED current setting.

Alternatively to internal LDO, device circuitry can be powered from external power supply (4.4...5.25 V)
connected to LDO pin. The internal LDO is disabled in this case.

6.1

PWM input to Initiate Start-up Sequence

The backlight is started by setting PWM input high. By default, LP8862-Q1 EVM has PWM input set high
(100% duty cycle). It is connected to VDDIO through jumper J2. Alternatively, an external PWM signal can
be connected by removing jumper J2 , shorting pins 3 and 4 on jumper J17 and connecting the external
PWM to connector J18.

Figure 5. Typical Start-up Sequence

6.2

Shutdown Sequence

The backlight is shut down (LEDs turned off) by setting PWM input low or when VDDIO/EN = 0. If
VDDIO/EN is set low, the LP8862-Q1 enters low-power mode with internal LDO disabled.

8

LP8862-Q1EVM Evaluation Module

SNVU478A – July 2015 – Revised October 2015

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Copyright © 2015, Texas Instruments Incorporated

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Содержание LP8862-Q1EVM

Страница 1: ...Using the LP8862 Q1EVM Evaluation Module User s Guide Literature Number SNVU478A July 2015 Revised October 2015 ...

Страница 2: ... Start up Sequence 8 6 2 Shutdown Sequence 8 7 Boost Converter 9 7 1 Switching Frequency 9 7 2 Spread Spectrum and Synchronization 9 7 3 Voltage Control 10 8 LED Current Sinks 10 8 1 Output Configuration 10 8 2 Current Setting 10 8 3 Brightness Control 11 9 Fault Detection 11 9 1 Fault Indicator 11 10 Evaluation Board Schematic 12 11 Bill of Materials 13 Appendix A LED Load Board 14 Revision Histo...

Страница 3: ...ut Voltage vs R12 10 8 Output Current vs RISET 11 9 Evaluation Board Schematic 12 10 LED Load Board Top Side 14 11 LED Load Board Bottom View 14 12 LED Load Board Schematic Diagram 15 13 Forward Voltage for Cree Xlamp ML B LEDs 16 List of Tables 1 Bill of Materials for LED Load Board 16 3 SNVU478A July 2015 Revised October 2015 List of Figures Submit Documentation Feedback Copyright 2015 Texas Ins...

Страница 4: ... required to correct this interference 1 4 If You Need Assistance Contact your local TI sales representative 2 Introduction The Texas Instruments LP8862 Q1EVM evaluation module EVM helps designers to evaluate the operation and performance of the LP8862 Q1 device The LP8862 Q1EVM uses the LP8862 Q1 to drive up to 2 LED strings for LCD backlighting with high efficiency Information about output volta...

Страница 5: ...from 4 5 V to 40 V to support automotive stop start and load dump condition LP8862 Q1 supports PWM brightness dimming ratio up to 10 000 1 for input PWM frequency of 200 Hz The LP8862 Q1 integrates extensive safety and protection features 3 1 Features Two High Precision Current Sinks Current Matching 1 typical Output Current up to 160 mA Channel Dimming Ratio 10 000 1 at 200 Hz PWM input Integrate...

Страница 6: ...OL POINTS Hardware Setup www ti com 4 Hardware Setup Figure 1 shows connectors and main components on the LP8862 Q1 board Figure 1 Evaluation Board Connectors and Setup 6 LP8862 Q1EVM Evaluation Module SNVU478A July 2015 Revised October 2015 Submit Documentation Feedback Copyright 2015 Texas Instruments Incorporated ...

Страница 7: ... Layer GND See the LP8862 Q1 data sheet for PCB layout guidelines Figure 4 Evaluation Board Stackup 4 layer board FR4 Material thickness 1 616 10 mm Surface finish immersion gold 7 SNVU478A July 2015 Revised October 2015 LP8862 Q1EVM Evaluation Module Submit Documentation Feedback Copyright 2015 Texas Instruments Incorporated ...

Страница 8: ...r J4 connecting R3 160 kΩ to FSET and boost maximum voltage is 37 V R12 750 kΩ and R13 130 kΩ See Section 7 1 and Section 7 3 for descriptions of how to change boost settings By default LED current is 160 mA per string jumper J5 connecting R4 30 kΩ to ISET See Section 8 2 for descriptions of how to change LED current setting Alternatively to internal LDO device circuitry can be powered from extern...

Страница 9: ...uency remove jumper J4 short pins 7 and 8 on jumper J17 and connect the external resistor to connector J18 Boost internal parameters will be adjusted automatically according to chosen frequency 7 2 Spread Spectrum and Synchronization The SYNC pin is used to enable boost spread spectrum or alternatively to synchronize boost switching with an external frequency To disable spread spectrum functionali...

Страница 10: ...ltage is about 88 of maximum voltage Boost output voltage is adjusted automatically based on LED current sink headroom voltage Default setting for boost maximum voltage is 37 V R12 is 750 kΩ 8 LED Current Sinks 8 1 Output Configuration The LP8862 Q1 detects LED output configuration during start up Output connected to ground is disabled and excluded from adaptive boost control and fault detections ...

Страница 11: ... J18 For test purposes the PWM input of LP8862 Q1 can be connected to ground to turn off LEDs or connected to VDDIO EN to set up 100 brightness using jumper J2 9 Fault Detection 9 1 Fault Indicator The LP8862 Q1 has fault detection for LED open and short VIN input overvoltage VIN undervoltage lockout power line overcurrent boost overcurrent and thermal shutdown An open drain FAULT pin indicates fa...

Страница 12: ... www ti com 10 Evaluation Board Schematic Figure 9 Evaluation Board Schematic 12 LP8862 Q1EVM Evaluation Module SNVU478A July 2015 Revised October 2015 Submit Documentation Feedback Copyright 2015 Texas Instruments Incorporated ...

Страница 13: ...il above insulator J18 Header TH 100mil 10x1 Gold plated 230 Samtec TSW 110 07 G S 1 mil above insulator J25 Conn Term Block 2POS 3 81mm TH Phoenix Contact 1727010 1 L1 Inductor Shielded 22uH 3 7A 0 103 ohm Vishay Dale IHLP3232DZER220M5A 1 SMD Q1 MOSFET P CH 60V 30A Vishay Siliconix SQJ461EP 1 PowerPAK_SO 8L R1 RES 0 05 ohm 1 3W 2512 Bourns CRA2512 FZ R050ELF 1 R2 RES 20k ohm 5 0 1W 0603 Vishay Da...

Страница 14: ...s Cree Xlamp ML B LEDs with maximum current 175 mA and maximum forward voltage 3 5 mA at 80 mA 3 3 V typical are used on the board NOTE The LED board is not included with the EVM contact your local TI sales representative if board is needed Figure 10 LED Load Board Top Side Figure 11 LED Load Board Bottom View 14 LED Load Board SNVU478A July 2015 Revised October 2015 Submit Documentation Feedback ...

Страница 15: ... 2 3 J58 1 2 3 J59 1 2 3 J60 1 2 3 J61 1 2 3 J62 1 2 3 J63 GND 1 2 3 4 J64 D80 D79 D78 D77 D76 D75 D74 D73 1 2 3 J77 1 2 3 J78 1 2 3 J79 1 2 3 J80 1 2 3 J81 1 2 3 J82 1 2 3 J83 1 2 3 J84 GND 1 2 3 4 J85 D100 D99 D98 D97 D96 D95 D94 D93 1 2 3 J98 1 2 3 J99 1 2 3 J100 1 2 3 J101 1 2 3 J102 1 2 3 J103 1 2 3 J104 1 2 3 J105 GND 1 2 3 4 J106 D120 D119 D118 D117 D116 D115 D114 D113 1 2 3 J119 1 2 3 J120...

Страница 16: ...der 100mi 2x2 Samtec TSW 102 07 G D 7 J127 J2 J21 J23 J42 J44 J63 J65 J84 J86 J105 Header 100mi 3x1 Samtec TSW 103 07 G S 121 J107 J126 J129 J130 Header 100mi 7x1 Samtec TSW 107 07 G S 1 D1 D120 Cool White SMD LED XLamp mL B Cree MLBAWT A1 0000 000W51 120 Figure 13 Forward Voltage for Cree Xlamp ML B LEDs 16 LED Load Board SNVU478A July 2015 Revised October 2015 Submit Documentation Feedback Copyr...

Страница 17: ...ion Page Changed Product Preview to Production Data status 4 NOTE Page numbers for previous revisions may differ from page numbers in the current version 17 SNVU478A July 2015 Revised October 2015 Revision History Submit Documentation Feedback Copyright 2015 Texas Instruments Incorporated ...

Страница 18: ...ring the warranty period to the address designated by TI and that are determined by TI not to conform to such warranty If TI elects to repair or replace such EVM TI shall have a reasonable time to repair such EVM or provide replacements Repaired EVMs shall be warranted for the remainder of the original warranty period Replaced EVMs shall be warranted for a new full ninety 90 day warranty period 3 ...

Страница 19: ... by Industry Canada to operate with the antenna types listed in the user guide with the maximum permissible gain and required antenna impedance for each antenna type indicated Antenna types not included in this list having a gain greater than the maximum gain indicated for that type are strictly prohibited for use with this device Concernant les EVMs avec antennes détachables Conformément à la rég...

Страница 20: ... connecting any load to the EVM output If there is uncertainty as to the load specification please contact a TI field representative During normal operation even with the inputs and outputs kept within the specified allowable ranges some circuit components may have elevated case temperatures These components include but are not limited to linear regulators switching transistors pass transistors cu...

Страница 21: ...F REMOVAL OR REINSTALLATION ANCILLARY COSTS TO THE PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES RETESTING OUTSIDE COMPUTER TIME LABOR COSTS LOSS OF GOODWILL LOSS OF PROFITS LOSS OF SAVINGS LOSS OF USE LOSS OF DATA OR BUSINESS INTERRUPTION NO CLAIM SUIT OR ACTION SHALL BE BROUGHT AGAINST TI MORE THAN ONE YEAR AFTER THE RELATED CAUSE OF ACTION HAS OCCURRED 8 2 Specific Limitations IN NO EVENT SHALL T...

Страница 22: ...esponsible for compliance with all legal regulatory and safety related requirements concerning its products and any use of TI components in its applications notwithstanding any applications related information or support that may be provided by TI Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which anticipate dangerous consequences of failur...

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