EVM Description
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Figure 2. Current Sense Resistors
5.2
LED Loadboard
Figure 3. LED Loadboard
4
LP8557EVM User Guide
SNVU285 – December 2013
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Copyright © 2013, Texas Instruments Incorporated
Page 1: ...0 duty cycle 3V input high level 6 Turn on power supply 7 Enable pulse stream output The LEDs will light at 50 brightness if a 50 duty cycle is used The brightness will vary with the positive duty cycle of the PWM input signal 3 Changing Boost Frequency and PWM Frequency on the LP8557EVM The LP8557EVM is configured to operate at 500 kHz boost switching frequency and 9 8 kHz PWM frequency by the re...
Page 2: ...esistor can be changed to a value from Table 6 of the LP8557 datasheet which is presented here Table 2 Setting Full Scale LED Current and Boost Compensation with an External Resistor RISET Ω0 Tolerance Boost Compensation Option ILED mA 470k 1M 5 1 5 300k 330k 5 1 10 200k 5 1 13 147k 150k 154k 158k 1 1 15 121k 1 1 18 100k 1 1 20 86 6k 1 1 23 75 0k 1 1 25 63 4k 1 0 5 52 3k 53 6k 1 0 10 44 2k 45 3k 1...
Page 3: ... The LP8557EVM kit includes the main evaluation board and an LED loadboard 5 1 Main EVM Board Figure 1 LP8557 EVM Main Board 3 SNVU285 December 2013 LP8557EVM User Guide Submit Documentation Feedback Copyright 2013 Texas Instruments Incorporated ...
Page 4: ...ption www ti com Figure 2 Current Sense Resistors 5 2 LED Loadboard Figure 3 LED Loadboard 4 LP8557EVM User Guide SNVU285 December 2013 Submit Documentation Feedback Copyright 2013 Texas Instruments Incorporated ...
Page 5: ...www ti com EVM Description 5 3 Kit Assembly Figure 4 Kit Assembly 5 SNVU285 December 2013 LP8557EVM User Guide Submit Documentation Feedback Copyright 2013 Texas Instruments Incorporated ...
Page 6: ...Main EVM Schematic www ti com 6 Main EVM Schematic Figure 5 LP8557 EVM Schematic 6 LP8557EVM User Guide SNVU285 December 2013 Submit Documentation Feedback Copyright 2013 Texas Instruments Incorporated ...
Page 7: ...ency energy and has not been tested for compliance with the limits of computing devices pursuant to part 15 of FCC or ICES 003 rules which are designed to provide reasonable protection against radio frequency interference Operation of the equipment may cause interference with radio communications in which case the user at his own expense will be required to take whatever measures may be required t...
Page 8: ... its gain should be so chosen that the equivalent isotropically radiated power e i r p is not more than that necessary for successful communication This radio transmitter has been approved 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 l...
Page 9: ...tained the Technical Regulations Conformity Certification as provided in Radio Law of Japan with respect to this product Also please do not transfer this product unless you give the same notice above to the transferee Please note that if you could not follow the instructions above you will be subject to penalties of Radio Law of Japan Texas Instruments Japan Limited address 24 1 Nishi Shinjuku 6 c...
Page 10: ...derations per the user guidelines Exceeding the specified EVM ratings including but not limited to input and output voltage current power and environmental ranges may cause property damage personal injury or death If there are questions concerning these ratings please contact a TI field representative prior to connecting interface electronics including input power and intended loads Any loads appl...
Page 11: ...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...
