heat-power consumption ethernet shield wiznet 5100 chip

Hello,

I've a 2424 77 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.

jm_wsb:
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.

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?

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

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)

-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 :slight_smile:

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

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.

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