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Texas Instruments — Technical Presentation (December 2014)
16 slides from Texas Instruments's technical presentation, Dec 3, 2014
Slide 1: bqTESLA Wireless Power TX Trouble shooting Guide
bqTESLA Wireless Power TX Trouble shooting Guide Rev 1.0 – Dec 3, 2014
Slide 2: TX Trouble Shooting
TX Trouble Shooting • This Guide is based around the bq500212A but is applicable to other TX designs. Key difference will be in the Sleep & Snooze circuit. • The User’s guide for the EVM is a good reference for a working circuit and expected performance. • Do not try to de-bug too much at once. – Us
Slide 3: Test Set-Up Configuration
Test Set-Up Configuration • When testing a new TX for the first time we recommend: – Test with a know good RX, TI has several EVMs that would work well. – Disable Sleep / Snooze mode by shorting the LED Mode resistor to ground. The Sleep & Snooze function will be internally controlled. Note-LED will
Slide 4: First Power up and standby
First Power up and standby • Check out steps—NO RX: – Good to check for short on the power bus before applying power. – Voltage regulators. • 3.3V, V33D • 5V, V-gate regulator (does not apply to bq500212A) • Voltage at top of power section, after current sense resistor. – Digital PWM • With no RX on
Slide 5: Normal Start Up with RX
Normal Start Up with RX • Check out steps—RX-NO load: – Monitor the TX Coil Voltage, RX V-rect and RX out. – Place RX on the TX and compare wave form with figure XX • The V-rect should rise above UVLO, 2.7VDC. • The SS, ID and Config packet should be visible • Next the voltage on V-rect will change
Slide 6: bq500212A & bq51013B Start Up
bq500212A & bq51013B Start Up Signal strength ID Configuration Packets Vrec is greater than UVLO bq51013 starts Power Transfer Tuning to 7.5V using control error packets Note that the first phase (extended digital ping) is at 175kHz. During Power transfer the freq is changed
Slide 7: Possible Problems at Start Up
Possible Problems at Start Up • For the TX to start or continue power transfer it must decode the packets set by the RX. – Problems in communication can be seen during the digital ping phase, RX will reply but the TX will still stop sending power. – During power transfer phase the TX must decode a v
Slide 8: Removed RX and TX shutdown after 1.5 sec
Removed RX and TX shutdown after 1.5 sec TX Stops power transfer after 1.5Sec RX Removed Note – TX continues Power Tranfer If no valid CEP are received in 1.5 sec the TX will stop power transfer
Slide 9: Failure to start
Failure to start RX Sends Packets but TX does not receive them Power transfer does not start Typical digital ping is 70mS Note TX will stop power Transfer Immediately during SS/ID/CONFIG stage After power Transfer Starts the 1.5 sec rule applies
Slide 10: Testing of Sleep and Snooze
Testing of Sleep and Snooze • Snooze ckt is used to reduce power during standby, device will power down of about 500mS • Sleep ckt is used to reduce power during charge complete or fault condition by turning the device off for about 4 seconds. • Enable external Sleep & Snooze by removing the short a
Slide 11: Snooze Time Out -- Standby
Snooze Time Out -- Standby 3.3V LDO EN pin / C22 TX 3.3V LDO Output TX Coil Voltage
Slide 12: Sleep Time Out --- EPT01
Sleep Time Out --- EPT01 3.3V LDO EN pin / C22 TX 3.3V LDO Output TX Coil Voltage
Slide 13: Power Section Problems
Power Section Problems • Power Transfer between the TX and RX will have an efficiency of about 74% but this depends on several factor. – Load—Efficiency will be low at light load, less 500mA. – TX Coils—It is recommended to use a standard WPC coil. TX coil design is difficult and time consuming. – R
Slide 14: Coil Drive bq500212A EVM at 1A Load
Coil Drive bq500212A EVM at 1A Load Drive A signal Drive B signal Coil C / L node Tank Voltage
Slide 15: Typical Start Up Problems you May see
Typical Start Up Problems you May see • What does a start up problem tell me? – Consistent digital ping width and RX replies • The TX is not decoding any of the packets from RX, Communication failure – During digital width will vary, see part of SS, ID and Config • During decoding if an error is det
Slide 16: For Further Reference – resources available on-line
For Further Reference – resources available on-line • TI Wireless Power Landing Page: www.ti.com/bqtesla • Application Notes and Articles on TI Website (type in literature number – “SLxxx” into the search window at www.ti.com to access each document): – SLUA649: “bqTESLA Transmitter Coil Vendors” Ap
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