Hi I am designing a very simple buck converter. Just to test equations that is given in application notes from various electronic manufacturers. The MOSFET I will be using is STP14NK50Z (N Channel). Here is the parameters for my buck converter: Vin: 60V Fsw: 30kHz Vout: 48V Iout: 10A Before I start the design of the buck converter, I want to to calculate what driver I will be requiring. Calculate Current required from Gate Driver Idriver = Qg/dT, where Qg = 73nC and according to the AN799 app note dT = Turn-on/turn-off time, now I dont know if they mean Turn-on OR turn-off time or Turn-on Divide by turn-off time.
Stargate Sg-1 Rpg Pdf. 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. MOSFET Driver with Dual Outputs for Synchronous Buck Converters The NCP3420 is a single Phase 12 V MOSFET gate driver. MOSFETs in a synchronous buck converter.
So i took the absolute worst case, took td(on). (Table 7) This resulted in: Idriver = Q/dT = 73nC / 24nS = 3A. The current that the gate driver is suppose to supple seems quite high. Can you guys have a look through and suggestions/comments are welcome!! Ok I looked at the datasheet of the IRS21851SPbF, but I am confused. Problem The Vho pin from the driver is going to the gate of the MOSFET. (Vgs signal).
In the datasheet it says Vho(min) = Vs and Vho(max) = Vb. If i look at the 'typical connection' diagram on page 1 of the high side driver datasheet, they connect Vcc through a diode to Vb. Thus the Capacitor sitting between Vb and Vs, will be charge to Vs+ (Vcc-0.7V(diode)), Vs is the reference for the capcitor.
However Vs is connected to the source of the MOSFET, which does not make sense to me. The voltage on the source of the mosfet will be 0V because if my supply voltage to the drain of my mosfet is 50V, it will mean my Vgs must be 60V at least, and the Vgs at that point in time will be: Vcc for gate driver: 15V Vgs = Vs + (Vcc-0.7V) = 0V + (15V-0.7V) = 14.3V whic is not nearl 60V? I hope I am wrong but if not what is the use of the typical connection diagram in the datasheet for a HIGH SIDE DRIVER, if the maximum voltage for Vgs is totally dependent on the Vcc for the gate driver IC?
The Vho pin from the driver is going to the gate of the MOSFET. (Vgs signal). In the datasheet it says Vho(min) = Vs and Vho(max) = Vb. If i look at the 'typical connection' diagram on page 1 of the high side driver datasheet, they connect Vcc through a diode to Vb. Thus the Capacitor sitting between Vb and Vs, will be charge to Vs+ (Vcc-0.7V(diode)), Vs is the reference for the capcitor. However Vs is connected to the source of the MOSFET, which does not make sense to me. The voltage on the source of the mosfet will be 0V because if my supply voltage to the drain of my mosfet is 50V, it will mean my Vgs must be 60V at least, and the Vgs at that point in time will be: Vcc for gate driver: 15V Vgs = Vs + (Vcc-0.7V) = 0V + (15V-0.7V) = 14.3V whic is not nearl 60V? Kiem The Offline Viet Hoa Full.
MOSFET driver specifically designed to drive four power N-Channel MOSFETs in a synchronous-rectified buck converter topology. These drivers combined with a HIP63xx. I designed a simple buck converter to meet the. Buck Converter with Gate Driver. Buck converters have a bootstrap gate driver 1 and an N-channel MOSFET.
I hope I am wrong but if not what is the use of the typical connection diagram in the datasheet for a HIGH SIDE DRIVER, if the maximum voltage for Vgs is totally dependent on the Vcc for the gate driver IC? Click to expand.The charge pump bootstrap capacitor generates a voltage that is 14.3V above the source voltage. As the source voltage rises during turn-on (VB connected to HO), this voltage rise is transmitted to VB through capacitor C1 and then through VB to HO. Since there is already 14.3V on the capacitor to start, the voltage at VB (and thus the gate) rises at 14.3V above the source voltage (ignoring any losses). For a 60V drain voltage, the gate voltage would thus be 74.3V when the transistor is fully on. Note on the data sheet, that device is not recommended for new design.