A Lower Forward Voltage Drop Does Not Always Bring Benefits
Schottky barrier diode (SBD) is a unipolar device, which means electron (majority carrier) is the only carrier that conducts current during the normal operation of the Schottky diode. SiC, because of its wide bandgap, exhibits a higher Schottky barrier compared to Si and consequently a higher cut-in voltage (the forward-biased voltage where the diode starts conducting). However, the higher Schottky barrier and dielectric strength of SiC also enable the voltage rating of the SiC Schottky diode to easily reach 3300V. In the meantime, the voltage rating of the Si Schottky diode rarely exceeds 200V. Today, SiC Schottky diodes have replaced Si PiN diode (which is a bipolar device with a much higher reverse recovery charge and longer reverse recovery time) in many applications as switching diodes.
The forward voltage (VF) is one of the parameters people care about most in the datasheet of the SiC Schottky diode because it is directly related to the conduction loss. However, a paper published by Stanford scientists suggested that the junction capacitive charge (Qc) is another parameter as important as VF. The authors compared commercial SiC Schottky diodes and showed that the diode with a higher VF and a lower Qc can outperform the diode with a lower VF but a higher Qc, depending on the operation conditions. The reason is that the diode also dissipates energy during each cycle of charging and discharging its junction capacitance.
That says VF*Qc is a better measure (figure-of-merit) that should be used to evaluate the performance of the SiC Schottky diode. Generally, if the rms current is relatively low and/or the switching frequency is relatively high, choosing low Qc rather than low VF will give you a better chance to improve the efficiency.
- |
- +1 赞 0
- 收藏
- 评论 0
本文由热心市民小陈转载自fastSiC，原文标题为:A lower forward voltage drop does not always bring benefits，本站所有转载文章系出于传递更多信息之目的，且明确注明来源，不希望被转载的媒体或个人可与我们联系，我们将立即进行删除处理。
相关推荐
蓉矽1200V 30A SiC SBD（NC1D120C30KT）应用于40kW单向充电模块，电路损耗降低180W
本文以某品牌40kW单向充电模块为测试平台，对蓉矽SiC MOS和SiC SBD在该充电模块中应用表现进行了较为全面的测试。在该测试中，采用蓉矽NC1D120C30KT（1200V/30A/TO247-2）SiC SBD更换原机UFRD，蓉矽SiC SBD的Vf、Qrr以及trr均优于原机UFRD，且全功率范围效率高于原机，最大效率差为800V满载输出时，约0.45%，对应损耗降低180W。
瞻芯电子推出车规级1200V 60A SiC SBD产品，最高工作结温175℃，助力高效大功率应用
为了满足高效、大功率变换系统应用需要，瞻芯电子开发了4款1200V 60A SiC肖特基二极管（SBD）产品，其中TO247-2封装器件产品IV2D12060T2Z满足车规级可靠性标准（AEC-Q101），工作结温高达175℃，可承受10ms高达300A浪涌电流冲击，正向电压（Vf）为正温度系数，有利于二极管并联应用时电流平衡，且在高温下能保持稳定运行，保障了系统高效和可靠。
即思创意碳化硅肖特基二极管及MOSFET选型表
即思创意提供以下参数的技术选型,DC Blocking Voltage(V):650,Total Capacitive Charge(nC):10~45,Capacitance Stored Energy(μJ):1.6~6.5,Continuous Drain Current(A):2.5~60
|
产品型号
|
品类
|
Power Dissipation(W)
|
Continuous Drain Current(A)
|
Gate Charge(nC)
|
Output Capacitive Charge(nC)
|
Avalanche Energy(mJ)
|
|
FL12190A
|
碳化硅肖特基二极管
|
88
|
10
|
30
|
41
|
200
|
选型表 - 即思创意 立即选型
电子商城
现货市场
授权代理品牌：集成电路
授权代理品牌：分立元件
授权代理品牌：接插件及结构件
授权代理品牌：部件、组件及配件
授权代理品牌：电源及模块
授权代理品牌：电子材料
授权代理品牌：仪器仪表及测试配组件
授权代理品牌：电工工具及材料
授权代理品牌：机械电子元件
授权代理品牌：加工与定制
我要提问
登录 | 立即注册
提交评论