UCD90124A: Question about tachometer inputs

Sincheol Kim

Intellectual 400 points

Part Number: UCD90124A
Other Parts Discussed in Thread: UCD90910

Hi,

I'm Kevin Kim, a FAE supporting TI customers in Korea.

I have received inquiries from one customer who is considering to use UCD90124A as PWM FAN Controller.

Can you please check the questions below and give answers.

The UCD90124A datasheet describes that up to four GPIO pins can be used as tachometer inputs.

Q1. Does this mean that UCD90124A can support up to 4 tachometer inputs?

Q2. Which pins can be used as tachometer inputs?

PWM1/GPI1~PWM4/GPI4? or Any GPIO pin between GPIO1~GPIO4 and GPIO13~GPIO18?

Regards,

Kevin.

over 3 years ago

0 yihe over 3 years ago

TI__Guru 58060 points

Hello Kevin

Thank you for reaching out.

UCD90124A can support up to 4 fan(4 tacho inputs, 4 PWM output)

Any GPIO can be used for tacho input but PWM1-4 are preferred since those 4 pins can not be used as GPO output

Regards

Yihe

0 Sincheol Kim over 3 years ago in reply to yihe

Intellectual 400 points

Hello Yihe,

Thanks for your feedback.

If the customer has further question, I will update it.

Otherwise I will resolve this ticket.

Regards,

Kevin.

0 Sincheol Kim over 3 years ago in reply to Sincheol Kim

Intellectual 400 points

One more question from the customer.

The datasheet describes that UCD90124A can support up to 4 FANs and you also confirmed it.

But the customer would like to know why it can support only up to 4 FANs despite there are enough PWN outputs and GPIOs.

Is it H/W limitation? or something else?

Regards,

Kevin.

0 yihe over 3 years ago in reply to Sincheol Kim

TI__Guru 58060 points

Hello

Yes, from hardware wise, device has enough IOs for more fan, but UCD90124A is a integrated power sequencing/monitor device. FAN control is just one function. We have to balance the functions to cover various application.

Regards

Yihe

0 Sincheol Kim over 3 years ago in reply to yihe

Intellectual 400 points

Hi Yihe,

Understood.

Thanks for your feedback.

Regards,

Kevin.

0 Sincheol Kim over 3 years ago in reply to Sincheol Kim

Intellectual 400 points

Hi Yihe,

Sorry but one more question.

The customer told me they need 6 FANs so I was going to recommend UCD90910 instead of UCD90124A.

Because UCD90910 can support up to 10 FAN controls.

However they also need up to 13 monitoring channels (12 * Voltage monitoring + 1 * Temperature monitoring).

From the datasheet, UCD90910 can support up to 10 rails voltages.

So UCD90910 also does not meet the customer's requirment.

I tried to find the device that meet their requirements but I couldn't.

Can you please let me know the device that can support the following functions?

- Voltage monitoring : 12 channels

- Temperature monitoring : 1 channel

- FAN Control : 6

Regards,

Kevin.

0 yihe over 3 years ago in reply to Sincheol Kim

TI__Guru 58060 points

Hi Kevin

Unfortunately, we do not have a device to meet both requirement.

is that ok to use 4 fan FPWM to control 6 fan? some fan can share the same PWM to drive the fan speed.

Regards

Yihe

0 Sincheol Kim over 3 years ago in reply to yihe

Intellectual 400 points

Hi Yihe,

Thanks for your confirm.

I will discuss it with the customer and let you know.

Regards,

Kevin.

0 Sincheol Kim over 3 years ago in reply to Sincheol Kim

Intellectual 400 points

Hi Yihe,

The customer decided to use UCD90910 instead of UCD90124A, although it did not meet all their requirement.

I resolved this ticket.

Thanks for your supports.

Regards,

Kevin.

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UCD90124A: Question about tachometer inputs