IEEE C62.37-1996 pdf download IEEE Standard Test Specification for Thyristor Diode Surge Protective Devices
2.4.2 temperature coefficient of breakdown voltage (Ay(BR); (dV(BRdTj): The ratio of the change inbreakdown voltage, VBR) to changes in temperature. Expressed as either millivolts per degreeCelsius (mV/C), or percent per degree Celsius (%”C) with reference to the 25 °C value of breakdownvoltage (mVC or %/C).(See 4.5.14.)
2.4.3 temperature derating: Derating with temperature above a specified base temperaturc, expressed as apercentage, such as may be applied to peak pulse current (See 4.5.16.)
2.4.4 thermal resistance (RaJl; RaJC; RaJA): The effective temperature rise per unit power dissipationof a designated junction, above the temperature of a stated external reference point (lead, case, or ambientunder conditions of thermal equilibrium.(See 4.5.17.)
2.4.5 transient thermal impedance (ZaJL; ZaJC; ZJA)): The change in the difference between thvirtual junction temperature and the temperature of a specifed reference point or region (lead, case, orambicnt) at the end of a time interval divided by the step function change in power dissipation at thcbeginning of the same time interval that causes the change of temperature-difference. (See 4.5.18.)
NOTE– lt is the thermal impedance of the junction under conditions of change and is generally given in the form of acurve as a function of the duration of an applied pulse
2.4.6 variation of holding current with temperature: The change in holding current, Iy, with changes intemperature, It is shown as a graph, (See 4.5,15.)
2.4.7 virtual junction temperature (Tj): A theoretical temperature representing the temperature othe junction(s) calculated on the basis of a simplified model of the thermal and clectrical hehavior of thedevice.(See 4.5.17-4.5.18.
2.5 Gated thyristor surge protection device (SPD)
These devices have a gate (G, g) terminal that controls the switching region characteristics and themain terminals provide the SPD function. Two gate types are possible, as this additional terminal may beconnected to either an intermediate p or n layer of the thyristor. The first is a p-gate device, which has thegate biased negatively with respect to the anode. The p-gate device provides negative transient voltage pro.tection with respect to the anode. The second is an n-gate device, which has the gate biased positively withrespect to the cathode. The n-gate device provides positive transient voltage protection with respect to thecathode.
The gated thyristor SPD has many forms. Options are single or dual switching quadrant, n-gate and/or pgate, forward or reverse conducting or blocking quadrants. The following definitions give the terms andparameters in general form with specific devices detailed, including the symbol and references inparentheses.
2.5.1 gate reverse current, adjacent terminal open (IGA; IGKo): The current through the gate terminalwhen a specified gate bias voltage, Vg, is applied and the cathode terminal for a p-gate device or anodcterminal for an n-gate device is open circuited. (See 4.5.20, common-gate configuration.)
2.5.2 gate reverse current, main terminals short-circuited (lGAS: IGAS/: The current through the gatcterminal when a specified gate bias voltage, Vg, is applied and the cathode terminal for a p-gate device olanode terminal for an n-gate device is short circuited to the third terminal. (See 4.5.2.)
2.5.3 gate reverse current, on-state (IgAz: A7): The current through the gate terminal when a specifiedgate bias voltage, VG is applied and a specifed on-state current, 1 is flowing. (See 4.5.22 and Figure 7b).
IEEE C62.37-1996 pdf download
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