MOS and bipolar gated thyristor: A thyristor with IGBT switching characteristics

The IGBT has become the device of choice in many high-voltage-power electronic applications, by virtue of combining the ease of MOS gate control with an acceptable forward voltage drop. However, designers have retained an interest in MOS gated thyristor structures which have a turn-off capability. These offer low on-state losses as a result of their latching behaviour. Recently, there have been various proposals for dual-gate devices that have a thyristor on-state with IGBT-like switching. Many of these dual gated structures rely on advanced MOS technology, with inherent manufacturing difficulties. The MOS and bipolar gated thyristor offers all the advantages of dual gated performance, while employing standard IGBT processing techniques. The paper describes the MBGT in detail, and presents experimental and simulation results for devices based on realistic commercial processes. It is shown that the MBGT represents a viable power semiconductor device technology, suitable for a diverse range of applications. © IEE, 1998.

Spice modelling of the superjunction IGBT

This paper presents a SPICE model of the SuperJunction Insulated Gate Bipolar Transistor (SJIGBT) [1]. SPICE simulation results are in good agreement with the DESSIS simulation results under DC conditions. This model consists of an intrinsic MOSFET and a parallel combination of a wide and a narrow base pnp BJTs. A parasitic JFET is also included to account for the restricted current flow between two adjacent p-wells. In addition the JFET component also models the additional depletion region caused by the transverse junction at the upper side of the n-drift region where the current is mainly transported via majority carriers.

Soft turn-on of NPT IGBT under Active Voltage Control

In this paper the soft turn-on of NPT IGBT under Active Voltage Control (AVC) is presented. The AVC technique is able to control the IGBT switching trajectory according to a pre-defined reference signal generated by a FPGA chip. By applying a special designed reference signal at turn-on, the IGBT turn-on current overshoot and diode recovery can be optimized. Experiments of soft turn-on with different reference signal are presented in this paper. This technique can be used to reduce the switching stress on the device and on other components of the circuit. © 2011 IEEE.

Investigation into IGBT dV/dt during turn-off and its temperature dependence

In many power converter applications, particularly those with high variable loads, such as traction and wind power, condition monitoring of the power semiconductor devices in the converter is considered desirable. Monitoring the device junction temperature in such converters is an essential part of this process. In this paper, a method for measuring the insulated gate bipolar transistor (IGBT) junction temperature using the collector voltage dV/dt at turn-OFF is outlined. A theoretical closed-form expression for the dV/dt at turn-OFF is derived, closely agreeing with experimental measurements. The role of dV/dt in dynamic avalanche in high-voltage IGBTs is also discussed. Finally, the implications of the temperature dependence of the dV/dt are discussed, including implementation of such a temperature measurement technique. © 2006 IEEE.

Integrated avalanche diode for 600 v Trench IGBT over-voltage protection

Avalanche multiplication has been one of the major destructive failure mechanisms in IGBTs; in order to avoid operating an IGBT under abnormal conditions, it is desirable to develop peripheral protecting circuits monolithically integrated without compromising the operation and performance of the IGBT. In this paper, a monolithically integrated avalanche diode (D av) for 600V Trench IGBT over-voltage protection is proposed. The mix-mode transient simulation proves the clamping capability of the D av when the IGBT is experiencing over-voltage stress in unclamped inductive switching (UIS) test. The spread of avalanche energy, which prevents hot-spot formation, through the help of the avalanche diode feeding back a large fraction of the avalanche current to a gate resistance (R G) is also explained. © 2011 IEEE.

Parameters influencing the performance of an IGBT gate drive

This paper presents an improvement of an IGBT gate drive implementing Active Voltage Control (AVC), and investigates the impact of various parameters affecting its performance. The effects of the bandwidths of various elements and the gains of AVC are shown in simulation and experimentally. Also, the paper proposes connecting a small Active Snubber between the IGBT collector and its gate integrated within the AVC. The effect of this snubber on enhancing the stability of the gate drive is demonstrated. It will be shown that using a wide bandwidth operational amplifier and integrating the Active Snubber within the gate drive reduces the minimum gate resistor required to achieve stability of the controller. Consequently, the response time of the IGBT to control signals is significantly reduced, the switching losses then can be minimised and, hence, the performance of gate drive as whole is improved. This reflects positively on turn-off and turn-on transitions achieving voltage sharing between the IGBTs connected in series to construct a higher voltage switch, making series IGBTs a feasible practice. ©2008 IEEE.

IGBT series connection under active voltage control

In this paper an Active Voltage Control (AVC) technique is presented, for series connection of insulated-gate-bipolar-transistors (IGBT) and control of diode recovery. The AVC technique can control the switching trajectory of an IGBT according to a pre-set reference signal. In series connections, every series connected IGBT follows the reference and so that the dynamic voltage sharing is achieved. For the static voltage balancing, the AVC technique can clamp the highest collector-to-emitter voltage to a pre-set clamping voltage level. By selecting the value of the clamping voltage, the difference among series connected IGBTs can be controlled in an accepted range. Another key advantage for AVC is that by changing the reference signal at turn-on, the diode recovery can be optimized. © 2011 EPE Association - European Power Electr.

700V smart trench IGBT with monolithic over-voltage and over-current protecting functions

An advanced 700V Smart Trench IGBT with monolithically integrated over-voltage and over-current protecting circuits is presented in this paper. The proposed Smart IGBT comprises a sense IGBT, a low voltage lateral n-channel MOSFET (M 1), an avalanche diode (D av), and poly-crystalline Zener diodes (ZD) and resistor (R poly). Mix-mode transient simulations with MEDICI have proven the functionalities of the protecting circuits when the device is operating under abnormal conditions, such as Unclamped Inductive Switching (UIS) and Short Circuit (SC) condition. A Trench IGBT process is used to fabricate this device with total 11 masks including one metal mask only. The characterizations of the fabricated device exhibit the clamping capability of the avalanche diode and voltage pull-down ability of the MOSFET. © 2012 IEEE.

Superjunction IGBT filling the gap between SJ MOSFET and ultrafast IGBT

In this letter, we report E off-versus-V ce tradeoff curves for vertical superjunction insulated-gate bipolar transistors (SJ IGBTs), exhibiting unusual inverse slopes dE off/dV ce > 0 in a transition region between purely unipolar and strongly bipolar device behaviors. This effect is due to the action of p-pillar hole current when depleting the drift layer of SJ IGBTs during turnoff and the impact of current gain on the transconductance. Such SJ IGBTs surpass by a very significant margin their superjunction MOSFET counterparts in terms of power-handling capability and on-state and turnoff losses, all at the same time. © 2012 IEEE.