TPS40170: TPS40170

Aim is to design a DC/DC switch mode converter for Automotive applications (12V-48V)

Controllable output voltage and current . (aim is also to measure the output current ) current measurement circuit.

Vin (From battery Vbatt) from 12V upto 48V as input to this Switch mode IC
Vout (less than or equal to Vin)
Iout (upto 6A)

A micro-controller to control the complete system, with CAN transciever to send and receive signals from the ECU (which has loads that will draw the current)

This output current has to be measured.

I hope I made clear, something similar to PMP7233 (Cranking simulator in Automotive)

Regards
Bhargav

Hello John ,

It seems, it measures current (upto 25A)..

Can I use Hall effect current sensor for that matter ?

This design is a cranking simulator which generates three different cranking pulses to test automotive systems up to 50W. A microcontroller sets the output voltage of a synchronous buck in the range of 2-15V accordingly to the programmed curves. Output current is in the range of 3.3-25A. It is a complete system and all the information necessary to build the device is available

Regards
Bhargav

I am going to assign this to the designer of that reference design. He may be able to more accurately answer your questions. So far as I can tell, the microcontroller only controls the output voltage waveforms to generate the required crank waveforms. The current is set externally by the load. It doesn't measure current up to 25 A, it is just the current limit that is set for 25 A.

Hi Bhargav ,

I have seen few similar automotive applications where Buck Boost drivers were used .Buck/Boost driver gives you the capability of changing the output voltage lower equal to or higher then input voltage . You may have a look at LM5175 which has built in ouput current limit and is easily programmable .

www.ti.com/.../lm5175.pdf
www.ti.com/.../lm5176.pdf

---Ambreesh

Hi Ambreesh ,

Thank you for the information. I shall look in the specification sheet .

A micro-controller with CAN transciever is what I was looking in the TI products, as in my application I wish to control the output of this DC\DC buck converter with a micro-controller and further ECU (where the load will be connected) .


Regards

Bhargav

Hi Bhargav,

you can control the output voltage and current of nearly any power supply. You just need some additional little circuitry.

Please have a look on my PMP10151:

It's a Sepic converter where you can adjust the maximum output voltage and the maximum output current (in this case it's the maximum current into the output capacitor, but you if you just place the shunt after the output capacitors, it controls the output current). Both signals (current and voltage) are interconnected and whichever is dominant controls the duty cycle.

Setting the output current and voltage is done with different approaches. One uses a so called VID interface, the other one uses a chip with I2C interface, which provides a similar functionality.

If you tell me your email address, I can send you two articles about this with a deep explanation.

The cranking simulator uses a VID interface to control the output voltage. The waveform is stored in a microcontroller. So this circuit changes the output voltage, but has no current limitation (besides the overcurrent protection from the IC itself).

Regards

Matthias

Hello Matthias, 

In my application , I will have a micro-controller with a CAN Interface, and also the loads (ECU) Electronic control unit which will draw currents up to 20A. 

Depending on the load. 

May be TPS40170 suits my purpose . But then I also need to check with suitable micro-controllers from other sources with CAN interface for my application purpose. 

The FB pin of TPS40170 (output voltage is feed back to this pin through a voltage divider network ( does it mean I can have series transistor) for PWM from Micro-controller )

Micro-controller connections already mentioned in the schematic , or you can send it with the articles about the current and voltage respectively to 

bhargav.jani@web.de 

 

 

Thanks again 

Regards 

Bhargav Jani