Products In This Thread

LTC7004 Recommended for New Designs
The LTC7004 is a fast high side N-channel MOSFET gate driver that operates from input voltages up to 60V. It contains an internal charge pump that fully...
Datasheet
LTC7004 on Analog.com

  • State Suggested Answer
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 39 subscribers
  • Views 816 views
  • Users 0 members are here
Options
Related 

        

            Post
             Go back to editing
        

    

    


    

    









		












	
	
			
	
			
		
	
	
		

		
LTC7004  Failure



		

			

									
					    徐鹏767
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Sep 1, 2020 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    I was using a LTC7004 to control the ON/OFF of a 8series LiIon battery. The nominal input voltage is 29.6V, the load is a constant power 160W camera. Use an electric load to do 160W constant power discharging test, sometime the LTC7004 is found broken
    


    When the discharging for the input battery is done, the undervoltage protection is on and there is no output (at this moment INP of the LTC7004 is 3.3V and load is 160W), the LTC7004 is more likely to be broken.
    


    Failure description: connect INP pin with either 3.3V or 0V, the TG and TS voltages of LTC7004 are the same, which leads to the disconnection of NMOS. When electrified, the impedance between TG and TS of LTC7004 is 1.6Ω (using a multimeter to check). When not electrified, the impedance is infinitely great.
    


    More tests: I tested the earth impedance of each pin with a multimeter, and compared the impedance with that of a normally functional LTC7004 and found no problem.
    


    Could anybody help me with the reason why the LTC7004 is broken and how can I do to with it?
    

     
    
									
			        
		
    

				
				
		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    


	















    
	
    
	
    
					



			








	
	
	
	



Parents
	
      
	

    • 
	
      



	
			
		
	



      
	
      
		
      
							
					
      
		
      
			
													0
							
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
			                            
                        
                on Sep 2, 2020 4:50 PM
            
            
					
      
	
      

		
		
      
					
      Hi
      

      Is D30 placed close to TS pin and GND pad on the PCB board?  Since the load is constant power load, load current could be high when the under voltage protection is ON.  This load current with cable/trace to the load inductance can pull TS pin below GND.  D30 diode should be placed as close as possible to TS pin.
      

      I also noticed that turn ON slew rate has been slow down by R27 and C53.  Check the power MOSFET SOA curve rating and make sure voltage and current across the power MOSFET during turn ON doesn't exceed the rating.
      

      I would recommend using the ultra low leakage diode such as BAS116,BAS416, and BAQ34 diode instead of 1N4148 diode.  I would also recommend using 4.7uF cap value for C52 instead of 0.1uF.
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
						
						
				
				
		
		
      
			
		
      
	
      

      

      • 

	
    



Reply

      


    • 
	
      



	
			
		
	



      
	
      
		
      
							
					
      
		
      
			
													0
							
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
			                            
                        
                on Sep 2, 2020 4:50 PM
            
            
					
      
	
      

		
		
      
					
      Hi
      

      Is D30 placed close to TS pin and GND pad on the PCB board?  Since the load is constant power load, load current could be high when the under voltage protection is ON.  This load current with cable/trace to the load inductance can pull TS pin below GND.  D30 diode should be placed as close as possible to TS pin.
      

      I also noticed that turn ON slew rate has been slow down by R27 and C53.  Check the power MOSFET SOA curve rating and make sure voltage and current across the power MOSFET during turn ON doesn't exceed the rating.
      

      I would recommend using the ultra low leakage diode such as BAS116,BAS416, and BAQ34 diode instead of 1N4148 diode.  I would also recommend using 4.7uF cap value for C52 instead of 0.1uF.
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
						
						
				
				
		
		
      
			
		
      
	
      

      

      • 


    


Children