文件名称:MOSFET-drive-resistance
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在MOSFET OFF状态时为了保证栅极电荷快速泻放,此时阻值要尽量小,这也是Rsink<Rsource的原因。通常为了保证快速泻放,在Rg上可以并联一个二极管。当泻放电阻过小,由于走线电感的原因也会引起谐振(因此有些应用中也会在这个二极管上串一个小电阻),但是由于二极管的反向电流不导通,此时Rg又参与反向谐振回路,因此可以抑制反向谐振的尖峰。这个二极管通常使用高频小信号管1N4148。
实际使用中还要考虑MOSFET栅漏极还有个电容Cgd的影响,MOSFET ON时Rg还要对Cgd充电,会改变电压上升斜率,OFF时VCC会通过Cgd向Cgs充电,此时必须保证Cgs上的电荷快速放掉,否则会导致MOSFET的异常导通。
-In the MOSFET OFF in order to guarantee the charge state grid fast xie put, this time the resistance must be as low as possible, this is also the reason Rsink < Rsource. Usually in order to guarantee quick xie put, can be in a parallel Rg diode. When xie put resistor is too small, because the inductance of the reasons go line can also cause resonance (so some application will also be in the diode crosstalk in a small resistance), but because of the diode s reverse current not conduction, at this time and participate in reverse Rg resonance loop, so can inhibit the reverse resonance peak. The diode usually using high frequency small signal tube N4148 1.
In actual use need to consider the MOSFET discharge gate has a capacitance Cgd extremely, the effects of the MOSFET ON Rg but also to Cgd when charging, will change voltage up slope, OFF VCC to Cgs charging through Cgd, this time must ensure that the charge ON a rapid Cgs OFF, otherwise, it will lead to the MOSFET abnormal conducti
实际使用中还要考虑MOSFET栅漏极还有个电容Cgd的影响,MOSFET ON时Rg还要对Cgd充电,会改变电压上升斜率,OFF时VCC会通过Cgd向Cgs充电,此时必须保证Cgs上的电荷快速放掉,否则会导致MOSFET的异常导通。
-In the MOSFET OFF in order to guarantee the charge state grid fast xie put, this time the resistance must be as low as possible, this is also the reason Rsink < Rsource. Usually in order to guarantee quick xie put, can be in a parallel Rg diode. When xie put resistor is too small, because the inductance of the reasons go line can also cause resonance (so some application will also be in the diode crosstalk in a small resistance), but because of the diode s reverse current not conduction, at this time and participate in reverse Rg resonance loop, so can inhibit the reverse resonance peak. The diode usually using high frequency small signal tube N4148 1.
In actual use need to consider the MOSFET discharge gate has a capacitance Cgd extremely, the effects of the MOSFET ON Rg but also to Cgd when charging, will change voltage up slope, OFF VCC to Cgs charging through Cgd, this time must ensure that the charge ON a rapid Cgs OFF, otherwise, it will lead to the MOSFET abnormal conducti
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