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参数资料
| 型号： | IRF7821 |
| 厂商： | International Rectifier |
| 英文描述： | Power MOSFET |
| 中文描述： | 功率MOSFET |
| 文件页数： | 9/10页 |
| 文件大小： | 210K |
| 代理商： | IRF7821 |
IRF7821
8
www.irf.com
Control FET
Special attention has been given to the power losses
in the switching elements of the circuit - Q1 and Q2.
Power losses in the high side switch Q1, also called
the Control FET, are impacted by the R
ds(on) of the
MOSFET, but these conduction losses are only about
one half of the total losses.
Power losses in the control switch Q1 are given
by;
P
loss = Pconduction+ Pswitching+ Pdrive+ Poutput
This can be expanded and approximated by;
P
loss =
I
rms
2
× R
ds(on )
()
+ I ×
Q
gd
i
g
× V
in × f
+ I ×
Q
gs 2
i
g
× V
in × f
+ Q
g × Vg × f
()
+
Q
oss
2
×V
in × f
This simplified loss equation includes the terms Q
gs2
and Q
oss which are new to Power MOSFET data sheets.
Q
gs2 is a sub element of traditional gate-source
charge that is included in all MOSFET data sheets.
The importance of splitting this gate-source charge
into two sub elements, Q
gs1 and Qgs2, can be seen from
Fig 16.
Q
gs2 indicates the charge that must be supplied by
the gate driver between the time that the threshold
voltage has been reached and the time the drain cur-
rent rises to I
dmax at which time the drain voltage be-
gins to change. Minimizing Q
gs2 is a critical factor in
reducing switching losses in Q1.
Q
oss is the charge that must be supplied to the out-
put capacitance of the MOSFET during every switch-
ing cycle. Figure A shows how Q
oss is formed by the
parallel combination of the voltage dependant (non-
linear) capacitances C
ds and Cdg when multiplied by
the power supply input buss voltage.
Synchronous FET
The power loss equation for Q2 is approximated
by;
P
loss = Pconduction + Pdrive + Poutput
*
P
loss =
I
rms
2 × R
ds(on)
()
+ Q
g × Vg × f
()
+
Q
oss
2
×V
in × f
+ Q
rr × Vin × f
(
)
*dissipated primarily in Q1.
For the synchronous MOSFET Q2, R
ds(on) is an im-
portant characteristic; however, once again the im-
portance of gate charge must not be overlooked since
it impacts three critical areas. Under light load the
MOSFET must still be turned on and off by the con-
trol IC so the gate drive losses become much more
significant. Secondly, the output charge Q
oss and re-
verse recovery charge Q
rr both generate losses that
are transfered to Q1 and increase the dissipation in
that device. Thirdly, gate charge will impact the
MOSFETs’ susceptibility to Cdv/dt turn on.
The drain of Q2 is connected to the switching node
of the converter and therefore sees transitions be-
tween ground and V
in. As Q1 turns on and off there is
a rate of change of drain voltage dV/dt which is ca-
pacitively coupled to the gate of Q2 and can induce
a voltage spike on the gate that is sufficient to turn
the MOSFET on, resulting in shoot-through current .
The ratio of Q
gd/Qgs1 must be minimized to reduce the
potential for Cdv/dt turn on.
Power MOSFET Selection for Non-Isolated DC/DC Converters
Figure A: Q
oss Characteristic
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相关代理商/技术参数 |
参数描述 |
|---|---|
| IRF7821GTRPBF | 功能描述:MOSFET MOSFT 30V 13.6A 9.1mOhm 9.3nC RoHS:否 制造商:STMicroelectronics 晶体管极性:N-Channel 汲极/源极击穿电压:650 V 闸/源击穿电压:25 V 漏极连续电流:130 A 电阻汲极/源极 RDS（导通）:0.014 Ohms 配置:Single 最大工作温度: 安装风格:Through Hole 封装 / 箱体:Max247 封装:Tube |
| IRF7821HR | 制造商:International Rectifier 功能描述:TRANS MOSFET N-CH 30V 13.6A 8SOIC - Rail/Tube |
| IRF7821PBF | 功能描述:MOSFET 30V N-CH HEXFET 9.1mOhms 9.3nC RoHS:否 制造商:STMicroelectronics 晶体管极性:N-Channel 汲极/源极击穿电压:650 V 闸/源击穿电压:25 V 漏极连续电流:130 A 电阻汲极/源极 RDS（导通）:0.014 Ohms 配置:Single 最大工作温度: 安装风格:Through Hole 封装 / 箱体:Max247 封装:Tube |
| IRF7821TR | 功能描述:MOSFET N-CH 30V 13.6A 8-SOIC RoHS:否 类别:分离式半导体产品 >> FET - 单 系列:HEXFET® 标准包装:1,000 系列:MESH OVERLAY™ FET 型:MOSFET N 通道，金属氧化物 FET 特点:逻辑电平门 漏极至源极电压(Vdss):200V 电流 - 连续漏极(Id) @ 25° C:18A 开态Rds（最大）@ Id, Vgs @ 25° C:180 毫欧 @ 9A，10V Id 时的 Vgs(th)（最大）:4V @ 250µA 闸电荷(Qg) @ Vgs:72nC @ 10V 输入电容 (Ciss) @ Vds:1560pF @ 25V 功率 - 最大:40W 安装类型:通孔 封装/外壳:TO-220-3 整包 供应商设备封装:TO-220FP 包装:管件 |
| IRF7821TRPBF | 功能描述:MOSFET MOSFT 30V 13.6A 9.1mOhm 9.3nC RoHS:否 制造商:STMicroelectronics 晶体管极性:N-Channel 汲极/源极击穿电压:650 V 闸/源击穿电压:25 V 漏极连续电流:130 A 电阻汲极/源极 RDS（导通）:0.014 Ohms 配置:Single 最大工作温度: 安装风格:Through Hole 封装 / 箱体:Max247 封装:Tube |
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