I am a programmer trying to dabble in electronics. I got a junior PCB designer to put an IPS2200 and the generated wire pattern together with an MCU and a motor driver. Some testing and consults later I discovered some big issues with the designer's work. For example, the USB differential pair is ...not. Also the SIN/COS coming out of the IPS2200 does not go into the ADC enabled pins of the MCU. I've now got a laundry list of issues to fix with various parts of the PCB. The only real mystery is the IPS2200 itself.
Before I pay PCBway to make another board for me I'd like to confirm that - everything else aside - the way I've got the IPS2200 laid out is good to go. I've tried several ways to power the board and read the voltage of the SIN or COS lines as I move the interference disk over the coils. I don't seem to get anything. I've tried holding the board in reset so the MCU pins are floating. I've confirmed there is signal coming out of the TX line into the coils. Can you please help me?
the IPS2200 provides the absolute electrical position of the rotor over a sin/cos output interface. if you have a 4-pole pair sensor design (like the evk) you'll see 4 sin/cos periods per full…
I did not use the recommended design. At the time I was not aware of it. here is the entire schematic for the PCB:
I have not programmed the gain stage. I must have…
I would recommend you to use a design from the Resolver 4.0 Catalog.
from the schematic you attached I see that the C5 is for sure far too large and the oscillator probably would not even start. C5 must…
the IPS2200 provides the absolute electrical position of the rotor over a sin/cos output interface. if you have a 4-pole pair sensor design (like the evk) you'll see 4 sin/cos periods per full 360° mechanical revolution. The I²C interface is needed only to the initial settings of the IC (e.g. gain setting, DC offset compensation, amplitude mismatch etc..).
To calculate the rotor position you need to get the sin/cos into 2 ADC of the MCU and calculate Arctan(sin/cos). the sin and cos signals are either differential or single ended. Differential would guarantee a larger dynamic and better robustness against disturbers (EMC).
With regards to your questions, have you used the schematic we recommend? schematic: https://www.renesas.com/eu/en/document/sch/ips2200-schematic-template?language=en&r=469876
layout without sensing element:
have you checked that the TX coil oscillates at the right frequency (around 3.5MHz)?
have you programmed the right gain stage?
how big is your airgap?
what is the material of the target?
we have released the Resolver 4.0 catalog which contains 80 reference designs plug and play, including BOM, ref schematic, gerber files, measurement report. have you check this out? maybe you'll find something that fits to your need straightaway: https://www.renesas.com/eu/en/document/resolver-40-catalog?language=en
how did you make the coil design? if you need an optimized one, we at Renesas can do it for you
do you have an IPS2200 evk to program the IC?
look forward to hearing from you.
I have not programmed the gain stage. I must have misread the documentation. I assumed it was ok out of the box. What do you recommend?
the air gap is less than 2mm. the target material is two copper layers on a PCB.
The coil design was from a Renesas app.
I have an STM32F103 on the board through which I can send i2c commands to the IPS2200.
from the schematic you attached I see that the C5 is for sure far too large and the oscillator probably would not even start. C5 must be calculated such that together with the TX coil inductance the resonance frequency is between 2 and 5 MHz (the best is 3.5MHz). f=1/(2*pi*sqrt(L/C)) where L=TX inductance and C=C5.
I would recommend to measure the resonance frequency of the transmitter and tune C5 accordingly
how did you do your coil design? how big is the TX coil inductance? on the schematic I do not see the rx coils
I used the "inductive coil design tool" to generate the coil pattern. I believe this is the settings I used....
All the coils are pictured in the OP, copied below... unless something is missing?
To learn how to connect the coil to the IC please check our webminar, we posted on the IPS2200 landing page: https://www.renesas.com/eu/en/document/resolver-40-catalog?language=en
Follow up: I have some success at last! Thank you all for your help.