Driving Peltier Device through L298N to control Temperature

Hi,

I want to drive peltier element to control temperature of one module. Peltier specifications are:
Imax = 9A and Vmax = 3.75V.

Such 4 peltiers are connected in series to control to module temperature.

I am planning to use L298N for driving it. As shown if I connect L298N two pins in series then I will be able to drive current upto 4A. But, to control my module temperature, Peltier is sinking average 4A current.
So, It I can't use single L298N IC as it will heat too much and also it will damage.

So, I want to know whether it is possible to use two L298N ICs in parallel to give higher current.
If so then please advice me for input and output pin connections.

Thanks & Regards,
Sachin Panchal

I am not sure why you want to use the L298, to drive the Peltier device, I would use IGBT's or Mosfet's. As far as I remember even 2 L298's will not handle 4A continous.

The L298N could be used as part of a switch mode controller but it's not really a good choice for this.

A simple way to drive the Peltier modules is with a voltage controlled current source operating in the linear region. A MOSFET or BJT is the device to use.

An IGBT cannot be used in the linear region (it will quickly fail, I've tried it) but can be used to build a switch mode controller. However, the forward drop across an IGBT is 2-4 volts and is better suited to high voltage circuits.

So, the practical choices are a linear regulator or a Buck switching regulator and for either circuit I would use an N-channel MOSFET.

If you list the power supply voltage and the control signal voltage range I'll post a simple linear regulator circuit.

i agree with David Cuthbert, I apollogise for the IGBT suggestion

I was thinking that you wanted a proportional controller. That is a controller where the average current through the Peltier is controlled in real time either by a series pass transistor or by a switching regulator.

However in some cases a Peltier is operated like the furnace in your home or apartment; a "bang-bang" controller is used. A bang-bang controller drives the Peltier either fully ON or fully OFF with no in between state. A temperature comparator senses and controls the Peltier with hysteresis provided so the circuit does not chatter (switch OFF/ON rapidly). For example, it will switch the Peltier ON when the temperature exceeds 10 deg C and shuts it OFF below 5 deg C. The hysteresis band is 5 degrees.