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Cholerny Spammer
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 Posted: Thu 9:08, 09 Dec 2010 Post subject: Moncler prezzi GBT using the control switch _316 g |
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GBT using the control switch gate resistance
Resistance by increasing the value of the gate to reduce 【to eliminate the over-voltage IGBT brought the risk of being damaged. Fast turn-on and off can cause du / dt and di / dt high, and therefore produce more electromagnetic interference (EMI), which may lead to circuit failure. Protection of IGBT's switching characteristics of diode gate resistance is also affected by the impact and limit the minimum value of gate resistance. This means that the IGBT's turn-on switching speed and can only be used to a freewheeling diode reverse recovery characteristics of a level compatible. Reduce gate resistance not only increases the IGBT over-voltage stress, and because the IGBT module di / out increases, also increases the freewheeling diode overvoltage limit. Through the use of specially designed and optimized with a soft recovery on-gate current turn-off gate current conduction in Figure 1 turn-off gate current and gate current input voltage and current input B of a (V) (A) 800200600504001002oo50O0, c:: Rg = 10Qtray11, ItRg: 15Q, cf,, \. ?, cIJ tunnel 5.00U600U700U800U900U ■ When reading circle (s) Figure 2IGBT shutdown of CAL (controlled axial lifetime) - diodes,[link widoczny dla zalogowanych], can make the peak reverse current, so that the bridge in the IGBT's conduction current is small. Gate drive circuit drives the output stage is a typical design, using two forms of configuration at the totem pole MOSFET, shown in Figure 3. Two MOSFET gate signal by the same driver. When the signal is high, N-channel MOSFET turns on when the signal is low, P-channel MOSFET turns on, resulting in a two-transistor push-pull output configuration. MOSFET output stage may have one or two outputs. According to the output stage has two outputs, or all the way, can be realized with one or two gate resistance (conduction,[link widoczny dla zalogowanych], turn-off) for symmetrical or asymmetrical gate control solution. 2, the calculation of gate resistance for low switching losses, IGBT modules without oscillation, low diode reverse recovery peak current and the maximum du / dt limitation, gate resistance must reflect the best switching characteristics. Usually in applications, rated several graph G v Nigeria / crown G (. F) of the current large IGBT modules connected to a smaller gate resistance drivers; Similarly,[link widoczny dla zalogowanych], small IGBT module rated current,[link widoczny dla zalogowanych], larger gate resistance . In other words, IGBT data sheet resistance values given for each design must be optimized. IGBT gate data sheet resistance value is specified, however, the best range of IGBT gate resistor value is generally the value of the data in the table and between the two times. IGBT data sheet is the minimum value specified in the specified conditions, twice the rated current can be safely shut down. In practice, the test circuit and the differences in various application parameters, IGBT gate data sheet resistance is often not necessarily the best value. About the resistance of the above-mentioned values (ie twice the data sheet value), can be used as a starting point for optimization to a corresponding reduction in gate resistance. Determine the optimal value eventually the only way is to test and measure the final system, the application of the minimum parasitic inductance, it is very important. IGBT turn-off for maintaining the voltage over the specified range of data tables is necessary, particularly in the short-circuit conditions. Peak current gate resistor grid M, the peak current will be reduced by increasing the gate turn-on and turn-off time and switching losses. The maximum peak current gate resistance and gate driver output respectively the minimum performance of most decisions. 3 design,[link widoczny dla zalogowanych], layout and troubleshooting application is to be able to withstand high current, gate resistance must meet certain performance requirements and have certain characteristics. Since high current gate resistor is recommended to use resistors in parallel form. This will result in a redundancy, if a gate resistor is damaged, the system may temporarily run, but larger switching losses. Choose the wrong gate resistance can cause problems. The selected gate resistor value is too large will cause excessive wear and tear, should reduce the gate resistance and should therefore bear in mind the application of the switch performance. High gate resistance may lead to long-running during the switch IGBT in the linear mode, leading to the gate oscillation. However, if resistance is not enough power and peak power, or the use of non-anti-surge resistors, gate resistance will lead to overheating or burning. During operation, the gate resistance has to bear the continuous pulse current, so the gate resistance must have a certain peak power capacity. Use of very small gate resistance will lead to higher du / dt or di / dt, but may also cause EMI noise. ■ Park L ≥) ‰
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