BQ79656EVM-021: Current Sense in Cell Simulation Mode

Florian Behlke

Part Number: BQ79656EVM-021

Tool/software:

Hi guys,

I am using the BQ79656EVM-021 with simulated cells and i have an external power source connected to VSTACK and GND.

Now I am trying to measure a current via the voltage on SRP/SRN Pins. I have an external shunt resistor with 4-Terminal-connection in my circuit. The two inner Pins of the shunt are connected to SRP / SRN. I read the Main Current High an Low register but i am only getting my external supply voltage as a result. Even if nothing is connected to SRP/SRN i read the supply voltage of the board from the register.

How can i read the actual voltage on PIN SRN/SRP?

Greetings

Florian

over 1 year ago

0 Florian Behlke over 1 year ago

Prodigy 20 points

And inside the Current High/Mid/Low registers of CS ADC is always the same value which is never updatetd.

0 David Ray over 1 year ago in reply to Florian Behlke

TI__Expert 7020 points

Hi Florian,

Did you enable ADC_GO in Continuous mode?

0 Florian Behlke over 1 year ago in reply to David Ray

Prodigy 20 points

Yes i did.

//CONFIGURE THE MAIN ADC
	WriteReg(0, ACTIVE_CELL, ACTIVECHANNELS-6, 1, FRMWRT_ALL_W); //set all cells to active
	WriteReg(0, ADC_CONF1, 0x04, 1, FRMWRT_ALL_W);  //LPF_ON - LPF = 9ms
	
//START THE MAIN ADC
	WriteReg(0, ADC_CTRL1, 0x2E, 1, FRMWRT_ALL_W); //continuous run and MAIN_GO and LPF_VCELL_EN and CS_DR = 1ms
	HAL_Delay(9+5*TOTALBOARDS);

0 Florian Behlke over 1 year ago in reply to David Ray

Prodigy 20 points

Ok I somehow solved it by my own.

My testing current was too small to be accurately measured and I used the wrong reading method in the ReadReg function. I switched from single device read to broadcast read.

But one question is left. The resulting voltage fluctuates havily. is there anything i can do about this?

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BQ79656EVM-021: Current Sense in Cell Simulation Mode