Yes I read the article and comments. There isn't any mention in the text or pictures about the values of the MOSFET's that I could find! perhaps i missed something
D1, C1 and C2 along with the IR2110 form the bootstrap circuitry. When LIN = 1 and Q2 is
on, C1 and C2 get charged to the level on VB, which is one diode drop below +VCC.on, C1 and C2 get charged to the level on VB, which is one diode drop below +VCC.
When LIN = 0 and HIN = 1, this charge on the C1 and C2 is used to add the extra voltageWhen LIN = 0 and HIN = 1, this charge on the C1 and C2 is used to add the extra voltage
– VB in this case – above the source level of Q1 to drive the Q1 in high-side– VB in this case – above the source level of Q1 to drive the Q1 in high-side
conguration. A large enough capacitance must be chosen for C1 so that it can supplyconguration. A large enough capacitance must be chosen for C1 so that it can supply
the charge required to keep Q1 on for all the time. C1 must also not be too large thatthe charge required to keep Q1 on for all the time. C1 must also not be too large that
charging is too slow and the voltage level does not rise sufciently to keep thecharging is too slow and the voltage level does not rise sufciently to keep the
MOSFET on. The higher the on time, the higher the required capacitance. Thus, theMOSFET on. The higher the on time, the higher the required capacitance. Thus, the
lower the frequency, the higher the required capacitance for C1. The higher the dutylower the frequency, the higher the required capacitance for C1. The higher the duty
cycle, the higher the required capacitance for C1. Yes, there are formulae available forcycle, the higher the required capacitance for C1. Yes, there are formulae available for
calculating the capacitance. However, there are many parameters involved, some ofcalculating the capacitance. However, there are many parameters involved, some of which we may not know – for example, the capacitor leakage current. So, I justwhich we may not know – for example, the capacitor leakage current. So, I just
estimate the required capacitance. For low frequencies such as 50Hz, I use betweenestimate the required capacitance. For low frequencies such as 50Hz, I use between
4747μμF and 68F and 68μμF capacitance. For high frequencies like 30kHz to 50kHz, I use betweenF capacitance
this is good information but i dont understand how i will achieve my 98volts to the gate of the highside MOSFET, and I don't understand how the 98volts is achieved on the gate of low side MOSFET. Do you see my problem
I will be using the setup in image 8 so can i just put in to the circuit MOSFET's that are adequate i.e. under 500volts??? thanks
e.g. IRF540N