Frequently Asked Questions

Currently we use lab bench supplies that have a large amount of voltage ripple, but these supplies are bulky and noisy. If we want to use for DC in for Xpow, what is your recommendation?

Most commercial power supply have high noise due to switching power supply. We recommend using linear supply as the DC supply source. You can find a quick explanation at this link :

Can this unit source current instead of voltage?

Yes, it can.

Can it measure both the current and voltage?

Yes, it can. We have voltage and current monitor circuits that measure real time output.

For multiconnector, it doesn’t seem like the patch panel will allow us to do arbitrary connections of the grounds/outputs so we would need to make sure that we route cables to the appropriate pins?

We have reconfigurable connectors / PCB which allow you to do arbitrary connections (please check our manual). The standard connector FFC and 2.54 mm pin out. We could create/customize according to your requirement.

I am interested in buying a multi-channel unit that can drive microheaters on the Triplex platform from Lionix. These heaters seem to require quite high voltage and power -- 25 or 30 V and about 500 mW of power -- to go through a full 2pi phase shift. Are you able to supply a board that can control, say, 32 of these heaters simultaneously?

Yes, we are able to supply your request with our new system specification up to 28 V and 500 mW on each channel. It can supply your 32 heaters simultaneously.

What is your multiconnector arrangement?

You can use ribbon cables or FFC connector and there are different types of multiconnectors. Please refer to the multiconnector manual, especially on the Xpow-40AX datasheet.

Would you be able to create a custom patch for the 120 channel unit or do we have to use multiple 40 channel units?

Yes, we can create a custom patch for the 120 channels.

Do you offer a version of the 120 with current reading on each channel?

Yes, Xpow-120AX-CC or 120AX-CCvCV is built in with current and voltage output reading. The Xpow-120AX-CV also can be upgraded with current reading. Please refer to our comparison chart on product page.

We want to use this for a lot of different chips so there isn't a set schematic. Are you able to create some sort of patch panel? If not that's okay we will just make our own separate PCB that does this. We would just need to know what sort of connector/cable we would need.

Yes, we can create patch panel depend on the requirement. Our standard Xpow-40AX has multi-connector that attach to the patch panel (with ribbon cable + connectors). You can refer to our datasheet.

Can all of the heaters be connected to a common ground so that we can use all 120 channels for controlling 120 independent heaters?

Yes, it can.

What is the sensor-actuator latency, and sampling speeds? Can we implement a closed-loop control algorithm (i.e., PID) that runs at 1-10 MHz? If not, what is the fastest that we can run such an algorithm?

The clock frequency runs on 16 MHz. The speed would depends on where you would like to put your algorithm scheme (directly on firmware or your workstation).

Can you confirm me that with the CCvCV (8 or 40 channels), we will be able to read the voltage while driving at constact current?

Yes, you would be able to read the voltage while driving a constant current with this type of Xpow.

Would we be able to read the voltage and current of each channel through it?

Yes, the current/voltage control and reading are processed through serial communication. The standard GUI is basically send the command to control the current and voltage and read output current and voltage on each channel via current/voltage sensor.

Does the USB connection act like a serial port one?

Yes, it does like a serial port. We use SPI to communicate from controller host to Xpow system.

Can you please send me more info on the specs and capabilities of the products listed on your website?

Please refer to the datasheet list. You can download and check the detail specification.

Is it possible to integrate your product into our chassis (meaning, we get the PCB from you and power it off our internal supply)?

Yes, it is possible but we need to discuss related to the connector arrangement.

Do you offer any OEM discounts?

Yes, please provide us with detail requirements.

Can any channels be configured to set current (I) or voltage (V)?

Yes, it can.

Is it possible to read both I and V regardless of how the channel is configured? (meaning, if the channel is set to 100 mA and we read V, can read the true current of is the theoretical setting returned... What kind of resolution is offered for I and V reads?

Yes, it is possible. We have embedded the current sense/shunt amp to measure current both the differential IN+ and IN- inputand the voltage applied to the VBUS with max precision measurement. The resolution for the current is 10 microAmp and voltage is 1 mV.

Do you have any high-current channels (like 150+mA/channel) to drive lasers?

Yes, we do. Our current standard for Xpow-XAX max output current is 300 mA/ch. We do have another type specifically for 14-pin butterfly package laser. It is th LDAX-XCC type with 1, 2 or 6 channel with max 1500 mA/ch.

I can see in the table below that you use the terms I-dynamic/V-dynamic and the abbreviations -CC / CV - accordingly. I suppose that stands for "Control Current" and "Control  Voltage" or something similar. Does this mean that the product that has one of these two description can control either the current output or the voltage output accrodingly but not both of them?

Yes, that is correct. You can refer CC or CV also as Constant Current and Constant Voltage.

So purchasing the applicable product we are limited to either one or the other?

Yes, this is true. But you can choose full option (please refer to the upgrade list). With full option you have unlimited capability of the system.

I am asking because in the scope of our application we need to be able to perform CC and CV. In more detail, we need to be able to set current and while doing so being able to measure voltage and also measure back the actual current value that is being set. And also the equivalent situation as before for sourcing voltage. So I could summarize it in the following: (a) source I, measure V, measure back the actual sourced I, (b) source V, measure I, measure back to the actual sourced V. Plus we need to be able to switch from state (a) to state (b) dynamically. For example take an I-V curve of a DUT using state (a) and then switch to (b) and take the same I-V curve again.

Yes, we also provide this type of product to other customer for automation in their photonic integration circuits test. The state can be configured with automation script such as Python.

I see that you offer products ranging from 3, 8, 40 up to 120 channels, in box and OEM forms. In our applications, we need to be able to set/measure up to 179 channels worst case. Is it possible to use multiple 40 and / or 120 channel devices combined together in order to add up to this number?

Yes, it is possible. Our technology also allow to daisy chain the device which provide virtually unlimited number of channels.

On further thing that I notice is the maximum values for voltage and current. 10 or 30 Volts would be Ok. Preferably 28, but maybe we can live also with 10. For current I have seen a value of 300 mA which is OK. So for example the Xpow-40AX-CV/CC could source up to 10 V and 300 mA per channel. And the Xpow-120AX-Box-CV can source up 28 Volt and 100 mA per channel. Is that so?

We are currently upgrading our 120AX-CV with 3x of 40AX. So you can source up power more as each DC in has its own DC source.

So far the nicest thing that has definitely caugh my attention is the Xpow-120AX-CV. The only thing I could "complain" about is that it is only V-dynamic and thus can only control voltage (if I am correct about this point). I would be great if we could have this Xpow-120AX-CV but with the V/I-dynamic description. Would that be possible?

Yes, it is possible. Please refer to our current released 120AX-CCvCV datasheet.

Another thing I would like to inquire about is cross talk between the different channels through their grounds, and whether that is something that you have thought about.

Method to solve the crosstalk is by using current mode on each channel or use feedback with voltage network control but it will require additional feedback input or sensor. From our experience with controlling max 40 channels heaters on silicon nitride photonic chip, the crosstalk can be compensated by readjusting the voltage input at the realted affected heaters. The crosstalk depends also on the isolation, spacing of the heaters and thermal transfer material on the photonic integrated circuits.

Do I also get negative voltage if needed?

It depends on the type of Xpow, we are currently have the static voltage Xpow-LNAX with negative voltage. The other type is Xpow-XAX-CV-Bip. This type provide positive and negative output or bipolar output rather than unipolar.

What type of connector do you use at the DC outputs?

The current standard for 8 ch DC output connector is the 2.54 mm pin header and fixed terminal blocks two position 3.5 mm ( For 40 ch, we have: 1. D-sub 25 pin + FFC + 2.54 mm pin header (M2) 2. Banana type multiconnector + 2.54 mm pin header (M3)

Can you custom or should we choose 40 ch as the spec?

We can customize the multi-connector depends on your need.

A power supply we are using now is weak for surge at ON/OFF. Do you have information related to this?

This can happen from many factors such as decays over time of component caused by softening oscilatory or switching inductive/capacitive loads.

Is it possible for you to expand up to 256 ch from 40 ch?

It could possibly daisy chained.

Would it be possible to request higher power output on each channel?

Yes, it is possible. We can configure the Xpow into your power requirement but it would need additional lead time.

Can we request a program in a PC for controlling Xpow, which can do at least: turn on/off, set the output volt (current) and monitor the output current (volt).

Yes, we are currently have the program to do this configuration (sequence program). Please refer to the software upgrade option.

We want to enhance the step size, can you provide 5 Volt max Volt setting type so we can increase the step size?

Yes, we can either reduce/remove the amplification or we can also increase DAC bit resolution.

Does Xpow also have the voltage reading/sensor on each channel to see the voltage when the output is current?

Yes, the Xpow-CCvCV is capable reading both voltage and current on each channel.

I want note spaces for each channel. Would it be possible to add them?

Yes, please refer to software upgrade. We have created note spaces option.

Can they output 10 mA / 40 V per channel?

Yes, it can but we would need to upgrade the DAC/amplifier part if this is the requirement. You would also need DC 60 V power supply. The 40 V per channel would be used 14-bit resolution.

Can Xpow-40AX-CC output negative current?

Yes, we can customised it depends on the need.

In the device manual a 300 mA of output current is indicated for each cahnnel. In the "Comment" column is indicated a max output current of 800 mA. Is that the total current for all the channels? In other words, if I got it right, each channel can potentially have an output current of 300 mA but the sum of all the cahnnel-output-currents cannot exceeds 800 mA, correct?

No, the 800 mA is not the total current for all channels. The 800 mA is the max capability of output regulator on each channel and digital reading of current output. Each channel can output 300 mA. The total channel can output 2400 mA in total (8 channel). We can customize the Xpow if you need higher current specification. Please contact us for more information.