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[on:]

Hello,

I've a 24*24 7*7 power monitorring / PID thermostat based on arduino mega 2560 with an ethernet sield v2.
The ethernet connection is used for system status page and to transfert once a day all the logged data from SD to PC.

 As you can read in a lot of topics, this chip becomes hot, and the side-effect: consumes also a lot of power.

Has anyone a trick to let this chip consumes less power ?

The only thing I can think of is to 'suspend' the ethernet during night.

Any advice is handy,
thanks,
Jeroen.

[Reply #1 on:]

As you can read in a lot of topics, this chip becomes hot, and the side-effect: consumes also a lot of power.

In fact, it's the other way round: the chip consumes a lot of power, and the effect is that it gets hot

If you have a way to get the chip to suspend or switch off when not in use, that's a good starting point for reducing the power consumption.

[Reply #2 on:]

Shutting down the power to the chip would definitely fix this.

I believe that Wiznet were preparing a chip with the possibility to power down the chip, but nothing's out yet. If you can, arranging a way of disconnecting the 3,3V power supply could fix this. However, you'd lose the server function on it.

Another thing, is it the chip getting hot or the 3,3V rectifier?

[Reply #3 on:]

Hello,

It's definitaly the W5100 chip that becomes extremely hot and uses a lot of power (I will try to measure this tonight, but I think around 4 W)
The regulator has no problem. (it is a 5 V) and does not become extremely hot.

Is it realy necessary to stop the power to this chip, can't I just disable the chip via CS/SS pin (bring pin 10 HIGH) ?

Thanks,
Jeroen

[Reply #4 on:]

Hi

It's definitaly the W5100 chip that becomes extremely hot and uses a lot of power (I will try to measure this tonight, but I think around 4 W)

This chip consumes around 150mA @ 3.3 V so 0.5W is usual. Chip is 'warm', but you can keep finger on it ! (chip is less than 50°C in 22°C ambient air on my desk)
> You probably have some hardware problem.Once finded your'll have less than 1W. Why is your regulator 5V ? 3.3V is needed (chip is 5V I/O tolerant when 3.3 V powered)

Is it realy necessary to stop the power to this chip, can't I just disable the chip via CS/SS pin (bring pin 10 HIGH) ?

Going further needs disconnecting power (+ spi lines to avoid drivin pins on an unpowered chip)
Toggling CS has no big effect. This chip as no sleep mode. (W5200 will have)

[Reply #5 on:]

-My W5100 chip measures around 48 °C   at Ambient Temperature of 24°C
-On the wiznet forum they say "it is normal don't worry about it"
-I would stop worrying if temperature was < 40 °C

-Any long term users of the arduino W5100 shield ?
-I just got mine rev 5

[Reply #6 on:]

Unless hardware changes on the shield (VCC, MOSI, SS, CLK switching) one way for chip's case temp reducing  is  : adding some heatsink.
Assuming 0,5W for power dissipation a small 20°C/W heatsink could reduce case temp from 48°C to 38°C  @24°C ambiant.