WayTooLate
Newbie level 2
This is my first time posting here. This problem has been killing me for a week now. Any help is greatly appreciated.
I'm building a small-scale version of a full bridge, buck-boost that will be later implemented for high voltages. I am using two IR2110 to drive the gates of the MOSFETs. Before implementing the full bridge, I tested each driver in a half bridge configuration successfully (with correct Vgs signals). The problem comes when I link the bridges together with the inductor. The converter is load dependent, but in the full bridge setup no current is being drawn from the power supply. I know these drivers are usually used in a H-bridge setup where Vsupply goes to the drain of both high side MOSFETs and this might have something to do with it. I'm thinking I need to add additional capacitors or resistors to the 'left side' of the bridge.
Specs: fs = 100kHz, DC = 60% (for top-left/bottom-right MOSFET), Coss (MOSFET) = 1.28nF
*Mistakes on the circuit diagram: Vcc = 13.5V; Vcc should be connected to anode of Schottky diode
UPDATE: Fixed. The main problem was the pull-up resistor on the open-collector output of the LM339 (quad comparator). When all four outputs were attached, I was drawing near 3 times the max current of the comparator. I remedied this by changing the 4 resistors from 330 to 2.2kOhms.
I'm still trying to solve issues with shoot-thru by adding adequate deadtime using the applications notes provided by IR: **broken link removed**
On pg. 19, they state that the propagation delays are already closely matched, but adding a resistor with a diode on the gate can add additional deadtime.
I'm building a small-scale version of a full bridge, buck-boost that will be later implemented for high voltages. I am using two IR2110 to drive the gates of the MOSFETs. Before implementing the full bridge, I tested each driver in a half bridge configuration successfully (with correct Vgs signals). The problem comes when I link the bridges together with the inductor. The converter is load dependent, but in the full bridge setup no current is being drawn from the power supply. I know these drivers are usually used in a H-bridge setup where Vsupply goes to the drain of both high side MOSFETs and this might have something to do with it. I'm thinking I need to add additional capacitors or resistors to the 'left side' of the bridge.
Specs: fs = 100kHz, DC = 60% (for top-left/bottom-right MOSFET), Coss (MOSFET) = 1.28nF
*Mistakes on the circuit diagram: Vcc = 13.5V; Vcc should be connected to anode of Schottky diode
UPDATE: Fixed. The main problem was the pull-up resistor on the open-collector output of the LM339 (quad comparator). When all four outputs were attached, I was drawing near 3 times the max current of the comparator. I remedied this by changing the 4 resistors from 330 to 2.2kOhms.
I'm still trying to solve issues with shoot-thru by adding adequate deadtime using the applications notes provided by IR: **broken link removed**
On pg. 19, they state that the propagation delays are already closely matched, but adding a resistor with a diode on the gate can add additional deadtime.
