FAN CONTROLLER

Howdy Eli,

Thanks for the post.  There are a couple of devices that may suit your need. Most of the devices mentioned below tie Fan control with temperature operation.  Since temperature is not a concern you may want to implement the devices in open loop, operated through software. The devices are the following:

AMC6821, LM96063, LM96163, LM64 and LM63.

The product I support is the AMC6821:

The AMC6821 is a temperature monitor and pulse-width modulation (PWM) fan controller, which communicates via I2C interface.  There are three different modes to select from, Auto Temp-Fan mode, Software-RPM mode, and Software-DCY mode.  Each mode controls the fan speed by changing the duty cycle of the PWM output.  Since temperature is not a concern, you can operate in Software-DCY mode.  There is a built in fan failure detection (FAN-FAULT) that asserts low when the fan runs at a speed below the predefined minimum RPM (set in registers).

The AMC6821 has One TACH input pin, and One PWM Output pin.  The devices I listed only have one each as well.  Since you need 5 pwm signals, you will need to use multiple devices.

Please let us know if this fits your design.

Best Regards,

Matt

Hi Matt

Look interest. Is the AMC6821EVM-PDK is the right EVM?

Is it including FAN? can it be used closed loop?

Can you advise your mail?

B.regards

Eli

Hi Eli,

The AMC6821EVM-PDK is the correct EVM for the AMC6821 device.  It is important to note that the current EVM software is only compatible with Windows XP Operating Systems.  The EVM does not include a Fan, but includes terminal headers that enable a simple Fan connection interface. 

• There are two different closed-loop control modes, the first is an Auto Temperature-Fan mode, and the second is the Software-RPM mode.
• The Software-RPM mode adjusts the PWM output to maintain a consistent fan speed at a user-specified target value -- basically the device functions as a fan speed regulator.

Best Regards,

Matthew Sauceda

Thanks.

How we can use it  if we do not have WINDOW XP?

Hi

Any recommendation/solution?

Hello Matt

We got some  additional questions:.

1.When the chip decides that a fan is out of range ? I mean : what is the range of the Tacho pulses? can we as the user  define this range ?

2. Can the user change the 100% duty cycle during the spin up to a lower duty cycle ?

3. Can the user change the 100% duty cycle during fan fail detection spin up to a lower duty cycle ?

4.How many devices can be in use when we have 1 I^C bus ? We want to use 10 chips for 10 fans .

Wetting your recommendation regarding the WINDOW XP 

Thanks

Howdy Eli,

The AMC6821 EVM is currently only compatible with Windows XP Operating systems.  The EVM uses an older interface board, the USBMODE EVM, which only operates with the earlier Windows XP driver.  There is no current plan to upgrade the software for this EVM, but if the demand for this product is great we can definitely relay the urgency for updated EVM software.

To answer your questions:

1.  The TACH limits are specified in the TACH Limit register.  The larger value of the TACH data corresponds to a slower speed.  When the TACH data are larger than the TACH-Low-Limit, the fan runs at a speed below the predefined minimum RPM.  When the TACH data are less than the TACH-High-Limit, the fan runs at a speed above the predefined maximum RPM. (page 19 of DS). These limits can be set in Reg 0x10, 0x11.

2.  In Software-RPM Mode, The user writes the proper value in the TACH Setting Register to set the target fan speed. The actual fan speed is monitored by an on-chip fan speed counter, and the results is stored in the TACH-DATA Register.  The actual speed is compared with the setting value.  If there is a difference, the duty cycle is adjusted.  You can reset the RPM value by writing to the TACH Setting Register.

3.  This can be set in the TACH Setting Register.

4.  The AMC6821 has two address bits, making it capable to share a maximum of 4 devices on one I2C Bus.  To include more devices, you may need more I2C lines, or a mux controller for the address lines.

Hope this information helps,

Matt

Hi Matt,

We like to get more clarification on some technical point regarding this component

  Follow are our questions :

1. What are the max. addresses we can configure with this unit.

Are it is possible to set 10 units in serials

1. There are a thermal  control option, can we select by command dual mode control options.

Mean By Thermal mode and by DCY mode?

1. Can we set different max. D.C. while start up or while fail ?

Mean, can we set the Spin-up start operation to max 60% ? instead to max 100%.

1. Not clear how or who will reset the Alarm bit inside the unit and outside send Alarm after getting the “Alarm  notice “
2. Not clear how or how we can configure the percentage speed failure range , in your data you speak for 7% of our of range then the unit will send Alarm

Are it possible to configure the speed getting from the Tacho as much we like to set the failure range.

1. Not clear how will responsible for the speed desired , are this is the D.C. we set, or it is the Tacho feedback?

Mean if we will use the DCY mode , are the Fan speed will be accordantly to our speed desire and the Tacho will cover the measurement of the equivalent speed , and will report on this.

1. After the Spin-up the unit will run on 33%DC , are this value configurable. Are we can set different Value.

 Can you advise your e-mail address? 

Hello Matt

Any news/feedback?

B.regards

Eli

Hello Eli,

To answer your questions:

1. Is it possible to have 10 units tied serially?

• The AMC6821 has two address bits, making it capable to share 4 devices on one I2C Bus.  To increase the number of devices on one I2C bus, you may need some kind of multiplexing scheme as there are only a maximum of 4 unique slave addresses.

2.  What is the difference between Thermal mode and DCY mode?

• To clarify this question it should be noted that the AMC6821 has three fan control modes: Auto Temperature-Fan mode, Software-RPM mode, and Software-DCY mode.
  • Both Auto Temp and Software RPM are closed-loop control, meaning that when all parameters are defined the modes allow the device to run as a stand-alone device without CPU intervention.
  • Software-DCY is open-loop.  In Software-DCY mode, the PWM duty cycle is set directly by the value written to the device.

3. Can the user set the spin-up operation at startup to 60% instead of 100%?

• The Fan Spin-Up is hard programmed to increase from 33.3% to 100% duty cycle, and then maintains this value for the remainder of the spin-up process.  This spin-up time duration can be changed by editing the STIME bits -- the time can be changed from 0.2 seconds to 8 seconds.  After the spin-up process completes, the fan speed is controlled normally through the register value (DCY mode) or via closed loop (Temp and Software RPM mode).
• Spin-up can also be disabled by setting the FSPD bit of the Fan Characteristics Register to '1'.

4. Alarm bit clarification

• When the TACH is set and both the TACH high limit and low limit have been programmed the fan-out-of-range interrupt can be enabled allowing the device to monitor that data from the TACH and when the speed is above or below it's defined limits it will generate an alarm that asserts the /SMBALERT pin to active low. (pg 19 of DS).  A complete block diagram is listed on page 32 of the DS, which describes the register settings with block logic.

5. Percentage Speed Fan failure

• The fan speed limits can be programmed into the TACH-High-Limit, and TACH-Low-Limit.  Therefore you can adjust the percentages and apply to these registers.

6. After Spin-up

• In Software-DCY mode (open-loop) the PWM output duty cycle changes to the target value (user input to 0x22) immediately after the user writes the desired duty cycle to the device registers.
• In Auto Temp-Fan Control mode, the AMC6821 runs stand-alone (closed-loop), and the mode optimizes fan sppeed for a given temperature to intelligently manage the system.
• In Software RPM, the AMC6821 runs stand-alone (closed-loop), and works as a fan speed regulator to maintain the speed at a programmable target value.

Best Regards,

Matt

Hi Matt,

1. The device have optional 9 I2C slave address. That's not enough for our design. Please ask TI if one of the following is possible:
   1. is it possible that TI holds another set of devices with different choices of I2C address? (other than the table below from the Datasheet)
   2. Maybe another device with extended range of I2C address is available?
   3. Any other solution they find relevant?

 2867.table.pptx

Can your advise you e-mail?( my is  eli@telsys.co.il)

Hello Matt,

1.Need your reply to above

2.see below additional questions:

• We ask for “dual”  alarm level, meaning we ask to monitor two low speed levels,

1. If  first ”1-LOW” level detected an first Alarm will be issued
2.  When second “2-LOW” level detected an second alarm will be issue.

                   ECI ask to not  detect the high speed , only the Low speeds, and we need two low alarm lines.

• We ask to generate and monitor 12 different level speeds.

Can this component monitor all this 12 Levels,  and issue alarm accordantly if the speed is not in range of the  predefined level ( for each speed out of 12)?

Are this possible in the AMC6821?

Howdy Eli,

I should have most of the information that you requested shortly, and will try to update the post later today.

Thank you for your patience,

Matt

Thanks Matt,

Customer asked to have direct contact with you for technical question.

Can you advise your e-mail address?tel?