HI, I'm developing a buck boost converter which should have the capability to take an input of 12 V and the produce an output of 5 - 30V
I'm using an IR MOSFET for this and also IR2118 highside driver for this.
My switching frequency is 16KHz.
The converter tropology that I'm using is the general buck boost topology. It produces a negative output.
V_out = - V_in*D / (1-D) , where D is the duty cycle of the PWM
Everything works fine until I increase the output to about 12V (which actually is -12V). afterwards the output goes haywire. So I started debugging and realized that the MOSFET driver Vs pin has a negative voltage limit. When my output is 12V, the voltage on the 2118 Vs pin w.r.t ground is about -12V when the MOSFET is switched off.
(in this topology, the voltage of the MOSFET source pin at MOSFET switch of is V_out, which in this case is -12V)
So I think I' hitting the negative limit of the Vs pin of the FET driver. Any suggestions as to what I should do to get out of this problem ? I've looked around at the other highside driver ICs and all that have a very low negative limit.
Hoping you all can figure out things here, I'm a bit desparate now.....
I'm using an IR MOSFET for this and also IR2118 highside driver for this.
My switching frequency is 16KHz.
The converter tropology that I'm using is the general buck boost topology. It produces a negative output.
V_out = - V_in*D / (1-D) , where D is the duty cycle of the PWM
Everything works fine until I increase the output to about 12V (which actually is -12V). afterwards the output goes haywire. So I started debugging and realized that the MOSFET driver Vs pin has a negative voltage limit. When my output is 12V, the voltage on the 2118 Vs pin w.r.t ground is about -12V when the MOSFET is switched off.
(in this topology, the voltage of the MOSFET source pin at MOSFET switch of is V_out, which in this case is -12V)
So I think I' hitting the negative limit of the Vs pin of the FET driver. Any suggestions as to what I should do to get out of this problem ? I've looked around at the other highside driver ICs and all that have a very low negative limit.
Hoping you all can figure out things here, I'm a bit desparate now.....
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