Applications

Forum Post: RE: the setting of FET ON constantly for UCC27201-Q1

Atsushi — Mon, 20 May 2013 09:26:00 GMT

Dear Mahmoud-san,

Could you please ignore the previous question?

I have a question. Do we need to care the lower FET operation in this situation (with charge pump for the upper FET ON constantly)?

Best reagrds,

Atsushi Yamauchi

Forum Post: RE: Confused about DRV8432 in parallel mode

Fernando Mart��nez — Mon, 20 May 2013 09:23:00 GMT

OK, thaks for your answer. I have another question. The current limit is independent for each output. Does that mean that if you set OC_ADJ at 7.4 A, you are actually limiting current at 14.8 A? Because each half bridge is managing half of the total current that is going through the motor.

Forum Post: RE: DRV8801

Ryan Kehr — Fri, 17 May 2013 21:54:00 GMT

Eli,

1) Up to 200kHz is acceptable on the ENABLE input. This should be more than enough for a motor application. Typically we see 30kHz used for most applications.

2) The input deglitch time is the only thing you need to be concerned with. The deglitch range is 400ns - 800ns (max). A pulse of this duration will be ignored.

3) Crossover is "dead-time" to avoid current shoot-thru. This is the transition time between switching one channel high and the other low or vice-versa. I need to research the propagation delay more.

Forum Post: RE: Low Noise, Fast H-Bridge

Ryan Kehr — Fri, 17 May 2013 20:57:00 GMT

Fatin,

Rise/fall times for DRV8837 are typically 100ns with a max. of 150ns as given in the datasheet. Although, I have to be honest and am not sure what the load was under these test conditions and for your load it will surely be different.

The EVMs are $25, so pretty cheap to check out.

http://www.ti.com/tool/drv8837evm

If you need a device in the family with a spice model, the DRV8832 has a model. Scroll down under the MODEL heading:

http://www.ti.com/product/drv8832

Forum Post: RE: driver for bipolar stepper (3-4A) with step and dir input

Ryan Kehr — Fri, 17 May 2013 18:14:00 GMT

Silvio,

We do not have anything in the portfolio other than what you mentioned at this time.

However, we are working on something so check back within 1-2 months time.

Forum Post: RE: How to rotate BLDC motor Counter-clock wise which is bundled with DRV8312-C2 Kit.

Hale Petersen — Fri, 17 May 2013 18:07:00 GMT

I was actually able to figure it out, sorry i didn't post back for others to see. I had to play around with the commutation states that the motor was running though. Some were more smooth than others, but the changes I made are shown below.

//original for clockwise rotation

if (hall1.HallGpioAccepted==5)

pwm1.CmtnPointer = 0;

else if (hall1.HallGpioAccepted==1)

pwm1.CmtnPointer = 1;

else if (hall1.HallGpioAccepted==3)

pwm1.CmtnPointer = 2;

else if (hall1.HallGpioAccepted==2)

pwm1.CmtnPointer = 3;

else if (hall1.HallGpioAccepted==6)

pwm1.CmtnPointer = 4;

else if (hall1.HallGpioAccepted==4)

pwm1.CmtnPointer = 5;

//mine for counter-clockwise rotation

if (hall1.HallGpioAccepted==6)

pwm1.CmtnPointer = 0;

else if (hall1.HallGpioAccepted==4)

pwm1.CmtnPointer = 1;

else if (hall1.HallGpioAccepted==5)

pwm1.CmtnPointer = 2;

else if (hall1.HallGpioAccepted==1)

pwm1.CmtnPointer = 3;

else if (hall1.HallGpioAccepted==3)

pwm1.CmtnPointer = 4;

else if (hall1.HallGpioAccepted==2)

pwm1.CmtnPointer = 5;

Forum Post: RE: Power upgrade to HV Motor Control and PFC kit

ChrisClearman — Fri, 17 May 2013 17:52:00 GMT

there is also a 10A fuse on the kit

be sure if you change the power module you look at the current scaling for the ADC input to make sure you can measure those values and then convert them appropriately in SW.

Forum Post: RE: Control of Ac Motors

ChrisClearman — Fri, 17 May 2013 17:49:00 GMT

V/Hz control of ACI motors is pretty straight forward, there are some old examples here: http://focus.ti.com/docs/toolsw/folders/print/sprc194.html

If you want to introduce an inner torque controller for better performance / dynamics I would look at InstaSPIN-FOC

Forum Post: AFE5809EVM and ultrasound probes @ 8MHz in CW mode

Enrico Urru — Fri, 17 May 2013 08:47:00 GMT

Hello, I need your help!

I want to know if it is possible to use the local oscillator internal on the AFE5809EVM card , to drive Ultrasound probes ( 8 Mhz), or if I need to use an external oscillator at 8 MHz., in CW Mode.

Then, in the User's Guide, (SLOU338A–October 2012–Revised November 2012), at page 23, paragraph 9.3, it is not clear how to set the capacitors configuration to use External Clock for CW Mode.

First, 8 capacitors are indicated (The manufacture default setup uses ON BOARD CLOCK, with which C154, C155, C156, and C157 are installed. To switch to an external clock, these four capacitors must be uninstalled and capacitors C49,C50,C52, and C53 must be installed) ,

then in the table 1 below, there are others 8 different capacitors (C27 ,C28, C100 , C102, C29, C30, C25 , C26) .

there's an error? what are the right capacitors?

Thanks a lot for your support!
regards,
Enrico

Forum Post: Help on PGA400 Offset Correction

Tushar Kulkarni — Fri, 17 May 2013 04:04:00 GMT

Hi,

In PGA400 I need to set Offset ZTC Compensation and Offset PTAT Compensation at sensor calibration time,

will it possible to put offset value in Register Bank and write to ZTC and PTAT register?

Logic I am thinking is, if I have resistive sensor then it may possible that it will have different offset at ambient temperature, I will set ZTC and PTAT Offset such as I will neutralize ADC count. For that I will put Hex value to Bank_0 REG 00 and 01 and PGA400 will put that value to ZTC and PTAT.

Will it possible?

Tushar

Forum Post: RE: TL720M05-Q1 stability for output capacitor

David Xu1 — Fri, 17 May 2013 02:22:00 GMT

Hi Atsushi-san,

From the latest bench testing result. Please select cap according to below request: Cout>=68uF, ESR between 1ohm and 5ohm range.

Please be aware, if electricity cap is selected, their ESR would increase significantly under low temp, customer should make sure the ESR of the cap should be in 1ohm and 5ohm range under all temp.

My suggestion is that after selecting output cap, do practical bench test on bench with customer.

Best regards

David Xu

Forum Post: RE: AFE44x0SPO2EVM

Praveen Aroul — Fri, 17 May 2013 01:58:00 GMT

Hello Hideyuki-san,

It depends on the performance required and what MSP430 is doing.

It is possible to combine the analog supplies as well. But this is something you have to prototype and test on your board.

Forum Post: RE: Unipolar Microstepping

Gabriel Mejia — Thu, 16 May 2013 22:51:00 GMT

It is solved, the circuit of FIG works well. the problem was on a track in contact with the pad under the DRV8825.

thanks

Gabriel Mejia Ruiz

Forum Post: RE: SN54AHC16244

Richard Biddle — Thu, 16 May 2013 21:51:00 GMT

If you need the MIL-SPEC part send me an email at s-biddle @ ti.com and I'll have someone from marketing contact you. If you can include quantity and when you need delivery that will speed things up.

Forum Post: RE: DRV8811EVM Question

Ryan Kehr — Thu, 16 May 2013 15:11:00 GMT

Mike,

In full step, your current waveform should look similar to below. Notice it is bi-directional current.

This is showing 1 phase and the step input is shown in channel 1. The other phase is 90 degrees out of phase.

Forum Post: TPS65381 - Watchdog related issue

mohamed mohideen — Thu, 16 May 2013 09:50:00 GMT

Hi,

Iam using TPS65381 in our application, Through SPI , Im trying to configure the registers of TPS65381(In diagnostic mode) based on our application needs But before that itself , It is going to safe mode. (Im using Watchdog Q&A mode and the controller is TC274)

The very first data i sent to TPS65381 is for holding the regulator in diagnostic mode( DIAG_EXIT_MASK = 1) with associated command

Could you please provide the solution to configure the register before it going to SAFE state.

Forum Post: RE: DRV8412 PWM help

Ivan Debelec — Thu, 16 May 2013 09:05:00 GMT

Hello again...

Can you please post here pictures from PWM input on DRV8412 kit??? If is possible i'd like to see all 4 PWM inputs at speed of 100 rpm and current aprox. 2A...

I'm trying to make my stepper move with C2000 Launchpad i get some rotation but sometimes i get some strange hitches...

Thanks...

Forum Post: Reagrding DDC264

hideyuki sakai — Thu, 16 May 2013 08:24:00 GMT

Dear, Sir.

My customer is evalating DDC264 for their system, now.

It is just brief, but could you please teach us following points.

1. Data sheet, page20, Figure 33.

CONV signal strobe will be needed to return to normal operation mode.

Is it a time duration definition of CONV signal strobe?

2. Data sheet, page14, Reset(/RESET).

After programming for configuration resister, Wait at least 4 conversions is required.

It is related above#1, 4 conversions might be waited after CONV signal strobe?

3. Data sheet, page 20, Configuration resister Read & Write Operation.

Described on "Optional readback of the Configuration resister is avaliable".

Readback should not be needed if a customer don't want to use it?

Best Regards,

Forum Post: RE: DDC264CZAW Solder profile

LeonardEllis — Thu, 16 May 2013 01:46:00 GMT

Hi Bill,

The DDC264 is a nFBGA package, and all aspects of assembly are covered in an App Note SPRAA99: http://www.ti.com/lit/an/spraa99/spraa99.pdf . Please have the CM and/or customer review, esp sections 4.4 and all of Chapter 5.

-Leonard

Forum Post: RE: Current consumption on SM28VLT32-HT

Wade VonBergen — Wed, 15 May 2013 23:28:00 GMT

The data sheet values are correct.

There is an application note in the product folder discussing means to minimize power consumption.

Regards,

Wade