My Notes for Wireless Power and Data Transfer (WPDX)
P. McGill
30Oct13

* Power by Proxi Proxi-Ring240
- We have 2 ea of PR240-P010 ST and PR240-P010 SR, which is the CANBus version.
- Input voltage range is 20 - 32 VDC.
- Allowable distance 0 - 6 mm, alignment 5 mm.
- Rated power output is 24 V at 6.5 A continuous, 10 A peak for 12 sec/min cycle (20%).
- Testing with our units show max 24 V at 5 A output (120 W).
- There is a current limit circuit on the receiver that uses an LTC6102 current sense amplifier to drive a comparator circuit which disables the secondary buck converter when the current limit is exceeded. The shunt resistor R705 is 5 milliohms, and the gain of the LTC6102 is 4.3 kohm / 100 ohm = 43. Each amp of load current yields 0.005 ohm x 1 A x 43 = 0.215 V. The reference for the comparator is D709, which is a TL431 shunt regulator producing 2.5 V. D709 isn't listed on the BOM but has markings "TAQU", so its a TI TL431AQDBZRQ1. The current limit is therefore 2.5 V / 0.215 V/A = 11.6 A.
- The LM5116 buck converter in the secondary also has a built-in current limit. The current sense resistor R710 is 10 milliohm, and the current sense voltage threshold is 110 mV. The current is therefor Ilim = 0.11 V / 0.01 ohm = 11 A.

* CAN bus
- My CAN-Net Education Board appears to be running at 125 kHz, but the Proxi-Ring, according to their Web site, is running at 250 kHz. The two can not talk.