In a project I do I have been using a combo of RFID reader IC TMS3701 and passive tag TMS37157 to power MSP430.
I wish to increase the read range to around 20cm. Does anyone know if there is a better solution or next gen product now?
Thx,
Nick
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In a project I do I have been using a combo of RFID reader IC TMS3701 and passive tag TMS37157 to power MSP430.
I wish to increase the read range to around 20cm. Does anyone know if there is a better solution or next gen product now?
Thx,
Nick
Hi Eddie:
Thanks for the reply!
Tag antenna is 3mm in diameter with ferrite core.
Reader antenna is around 200-300mm in diameter.
I am already using the UCC27424-Q1 power amp(similar model) at the reader output.
The transponder looks very similar to ri-trp-dr2b.
I have read a report using RI-RFM-007B-30 to further boost the reader power. However, I am not sure how small i can integrate part of the circuit to make it wearable?
I am ok with reducing the read distance to 10-15cm, but I need it to have great tolerance to angular misalignment between the two coils.
To us the main purpose of using TMS37157 and TMS3705 is to have a wireless power solution and a low power communication link so our transponder device does not need battery. I am open to suggestions of using other solutions.
thx,
nick
Nick,
How much current do you require on the tag side?
The RFM-007B could certainly improve your power output and range, but it is a larger module. I think this would meet your range requirement depending on how much power the tag side requires.
If you wanted to consider HF with the RF430FRL15xH, you would also need to have a higher power reader and/or larger tag antenna. This may be achievable with HF, but really depends on how much power you need on the tag side since the RF field strength will be significantly lower at 15 - 20cm.
Hi Eddie:
The current required on the tag side is 700uA at the peak when ADC is working. around 20uA idle and 300uA active.
Our current prototype with TMS37157 works fine, but we wish to improve the tolerance angle when coil misalign. We are charging a 10uF cap to be the power source for the tag. Our system takes measurement every few min, as Ti's Tiris system is sequential Half duplex, communication stage is kind of seperate from power transfer stage, it is ideal for us.
Regards,
Nick
1. No I do not have another suggested circuit for higher power.
2. I could potentially work to increase the range, but I have never experimented with something like this. I recommend testing the power transfer of the high Q antenna first before adding the mux.
3. When we are talking about a simple passive RFID tag, it is usually the reader not being able to detect the load modulated response. In the case where you are pulling significant current on the tag, the issue could be that the device is not receiving enough power. You could test this by measuring the voltage on the tag side at range and see if it is within the threshold.