LT1160 Not Working Accordng to Datasheet

Thread Starter

ashkarmalik

Joined Jul 1, 2012
112
I have Build a H-Bridge Using 2 LT1160 Mosfet Drivers.When I apply Signal on diagonal side of the drive then the motor (1Amp 24v) Starts to run in an start-stop Oscillating fasion.
 

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kubeek

Joined Sep 20, 2005
5,795
What kind of signal do you apply? You cannot keep the upper mosfet on all the time, because C1 gets discharged and you don´t have enough voltage to keep the mosfet on. You need to use PWM with less than 100% duty cycle, for example 95%.
 

bertus

Joined Apr 5, 2008
22,276
Hello,

In your schematic R8,R9 and R10 are 10 Ohm.
This will not work, the optocouplers likely will burn out.

Bertus
 

Thread Starter

ashkarmalik

Joined Jul 1, 2012
112
1)You mean ,If I am using Bootstrap Circuit to turn the upper mosfet then the Upper Mosfet would drain its stored charge with time!
2)I'll supply the gate driver with pwm on higher side and will let you know what is happening.
3)Are Mosfet gate driver available which can be continously kept on i.e High and Low Side ,And they uses Bootstarp circuit also?
 

kubeek

Joined Sep 20, 2005
5,795
You would either have to make a boost converter or charge pump to provide rougly 12V above the 24V rail, or use a P-channel mosfet for the upper transistors.
 

Thread Starter

ashkarmalik

Joined Jul 1, 2012
112
Thank you for clearing my doubt and pointing out the mistake,Really Appericiate you Effort,Once I would connect PWM on Upper side and run the setup then I'll Update the results.
 

Thread Starter

ashkarmalik

Joined Jul 1, 2012
112
I have Applied the 50%~95% Duty Cycle to Turn on the Upper side,But the same Response is been generated from the H-Bridge.
 

kubeek

Joined Sep 20, 2005
5,795
What response exactly? Also I noticed you have R16 connected wrong, it should go to the source not to the next gate, but that should not cause too much trouble.
 

Thread Starter

ashkarmalik

Joined Jul 1, 2012
112
What response exactly? Also I noticed you have R16 connected wrong, it should go to the source not to the next gate, but that should not cause too much trouble.
"R16 " is an error in the Schematic,It is connected to gate and Source.
Motor runs In jerking like fashion.i.e Speed up quickly and stops and keeps doing this repeatedly.
But I noticed some thing more on the H-bridge,When I switches the Other half of the Bridge then Sometimes the Drivers (LT1160)heats up quickly and I stops the test.
I have Changes the Bootstrap Cap to 0.1uF also.and tested the same result.(Just to know what is going on with the driver)
 

Thread Starter

ashkarmalik

Joined Jul 1, 2012
112
Thank you for waiting ,I have captured the specific signals for proper debugging.WP_20161010_006.jpg
This is the signal captured at the gate side of both the lower and upper side mosfet.
 

Thread Starter

ashkarmalik

Joined Jul 1, 2012
112
Yes,I am giving regular 50% duty cycle input at the top gate side ,And this is the result.and the bottom side is been supplied with a constant high signal.
 
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