Considerations for series connection of IGBT and MOSFET switches
28 May 2008
Power Electronics / Power Management
Information from Ixys
Figure 1 shows the typical RC snubber networks for voltage sharing for switches (S) connected in series in a capacitive discharge circuit. A static voltage sharing resistor RS is required so that the switch with the lowest leakage current is not forced into avalanche and a dynamic voltage sharing capacitor CS is needed so that the slowest switch is not forced into avalanche voltage breakdown during turn-on. A compromise must be reached between the number of switches in series, values for RS and CS and cost of the total switch.
The values of the resistors RS and capacitors CS can be computed from the following:
1. Static voltage sharing resistor RS:
RS ≤ (nVS(MAX) – VDC)(n – 1)-1 IS-1
where: n = number of devices in series
VS(MAX) = maximum allowable voltage across a switch (normally 80% of the maximum switch voltage rating)
IS = maximum leakage current of a switch.
Power dissipation in resistor RS:
2. Dynamic voltage sharing capacitor CS: Assuming no reverse current flow through the switches, then the major factor to consider in sizing capacitor CS is the voltage buildup on the last switch to turn-on. It is desirable to prevent the MOSFET from avalanching in order to limit its turn-on losses. The worst case scenario is that the switch sustaining the highest voltage is also the slowest to turn on.
Then:
where: ΔV = Avalanche voltage - VS(MAX)
DtD(ON) = difference in turn-on times
Solving for CS:
Further reading:
High-voltage IGBT
Hi-Q Electronics
Power Electronics / Power Management
Diotec Semiconductor has launched the DIW030M060 IGBT, a 600 V, 30 A device with a built-in reverse diode.
Read more...
DC converter for Hi-Rel applications
Vepac Electronics
Power Electronics / Power Management
The MFK2812S from Crane Aerospace & Electronics is a DC-DC converter with an input voltage range of 16 to 50 V and an output of 12 V at up to 2,08 A.
Read more...
Distributed Energy Resource Management Systems
Schneider Electric South Africa
Power Electronics / Power Management
In addition to grid stability, DERMS also play a role in energy trading with some countries leveraging DERMS for real-time energy trading.
Read more...
BYD introduces new energy storage solutions
Power Electronics / Power Management
BYD Energy Storage, a business division of BYD, has introduced the new BYD Battery-Box LV5.0+ at the recent Solar & Storage Live Africa in Johannesburg.
Read more...
Micro energy harvesting
Power Electronics / Power Management
Panasonic Industry and Miromico partner to show effective micro energy harvesting for industrial applications.
Read more...
Versatile 20 W PSU
Brabek
Power Electronics / Power Management
The new RAC20NE-K/277/EPID series from RECOM have a wide 85 to 305 V AC input range and deliver a full 20 W output power without derating.
Read more...
Battery monitoring and balancing IC
EBV Electrolink
Power Electronics / Power Management
The TLE9009DQU from Infineon is a multi-channel battery monitoring and balancing IC crafted for Li-Ion battery packs.
Read more...
New compact AC-DC PSU series
Vepac Electronics
Power Electronics / Power Management
COSEL has announced the expansion of its medical power offering with the addition of the new UMA series, the first three models being the 30 W UMA30F, the 60 W UMA60F and the 120 W UMA120F.
Read more...
Power efficiency and robustness in electronics design
Power Electronics / Power Management
Mouser Electronics recently announced a new eBook in collaboration with Analog Devices highlighting essential strategies for optimising power systems.
Read more...
USB Type-C-powered controllers
Future Electronics
Power Electronics / Power Management
Diodes Incorporated has released two USB Type-C PD 3.1 extended power range sink controllers that can be embedded into battery-powered devices.
Read more...
printer friendly version