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Unable to charge industry standard smart battery using LTC1960CG
DEMO CIRCUIT 1904A



		

			

									
					    malae.saisanthosh@ltts.com
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Sep 4, 2020 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Hi,
    

    I am trying to charge Industry standard smart battery using LTC1960CG DEMO CIRCUIT 1904A, i am successfully able to communicate with battery charger IC but unable to charge the battery.
    

    I have implemented following procedure,
    

    Hardware Setup:
    

      

    • DC Power supply of 15 - 20V/3.5A is given to DCin of LTC1960CG Demo Circuit 1904A
      • 

    •  Smart battery is connected to Battery 2 connector
      • 

    • MOSI, MISO, SCK and SSB pins from demo board are connected to MCU
      • 

    •  I2C lines of battery 2 are taken from P1 connector and connected to MCU
      • 

    • A Rheostat of 1k ohm resistance/150W is connected as load to DCout. 
      • 

    

    Programming:
    

      

    • Configured VDAC register.
      • 

    • Configured IDAC register.
      • 

    • Configured Charger write data to charge battery 2
      • 

    • Configured power path as Dc source
      • 

    • Periodically configuring charger write data register to avoid watchdog timer expiration
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    • Reading the status of charger IC
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    i am unable to charge the battery using this procedure, please let me know whether the configuration which i have done is incorrect and provide a solution to charge battery.
    
									
			        
		
    

				
						
        

		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    
















    
	
    
	
    
					



			








	
	
	
	



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													0
							
			
				
									
							        
			
			
			
        
            
						
                            
            
            				
            
                on Sep 7, 2020 8:33 AM
            
            
												
						in reply to ADIApproved
					
									
        
	
        

		
		
        
					
        Hello Zack,
        

        Thanks for response, battery model is NI2040 series and i had configured registers as follows,
        

          

        1. Configured VDAC register (Address b001) with the desired ChargingVoltage() value read from battery

            

          1. example : I received desired charging voltage as 12600mV and i had calculated VDAC value from the formula in LT1960 datasheet and written 0x87A8 in VDAC register
            2. 

          

          2. 

        2. Configured IDAC register (Address b000) with the desired ChargingCurrent() value read from battery

            

          1. example : I received desired charging current as 4000mA and i had calculated IDAC value from the formula in LT1960 datasheet and i had written 0x17E0 in IDAC register
            2. 

          

          3. 

        3. Written 0x4E in Charger write data register (Address b111) - Configured to charge battery 2
          4. 

        4. Written 0x26 in Power path register (Address b110) - Power path is set from DCin.
          5. 

        5. Written 0x0405 (Address b010) to read status register and always receiving 0x0202 as response, both DCDIV bit and CHARGING bit are not set.
          6. 

        

        Also periodically for every 300 msec, i am writing 0x4E to charger write data register to avoid watchdog timer reset.I am observing the LCD indicator on battery to confirm whether battery is charging or not. Please let me know if you required any more information.Thanks and Regards,Santhosh.
        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

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        •  Analog Employees  
        
            
						
                            
            
            				
            
                on Sep 8, 2020 2:27 PM
            
            
												
						in reply to malae.saisanthosh@ltts.com
					
									
        
	
        

		
		
        
					
        Hi Santhosh,
        

        

        So that would be an actual VDAC value of 1082 (base 10) which corresponds to VBAT value of ~17.3V according to my calculations. Subtracting 50 from the VDAC value and then running the equation I get:
        

        32752mV * (1082 - 50) / 2047 + 0.8V = 32752mV * 0.504 + 0.8V = 16.512V + 0.8V = 17.312V
        

        Can you double-check my conversions/calculations and yours?
        

        

        Regards,
        

        Zack
        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
						
						
				
				
		
		
        
			
		
        
	
        

        

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													+1
							
			
				
									
							        
			
			
			
          
            
						
                            
            
            				
            
                on Sep 19, 2020 8:39 AM
            
            
												
						in reply to ADIApproved
					
									
          
	
          

		
		
          
					
          Hello Zack,
          

          Sorry for delayed response. I had been sending MSB first from my MCU and actual sequence of data should be LSB first. Now, i had reversed all the bytes which are to be send to LTC1960 and it is working fine and i am able to charge the batteries.
          

          Thanks for your support.
          

          Regards,
          

          Santhosh.
          
			
          

		
			
	      

		
		
	
          
	
          
		
          
			
		
          
	
          
	
          
		
						
				
						
						
				
				
		
		
          
			
		
          
	
          

          

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