San Jose, CA and Singapore—it's a nasty job, but something has to do it: provide isolated, high-current gate drive for power IGBTs.
Why isolation? It solves many problems including ground loops, user and equipment safety, common mode noise, spikes, common mode voltages, and more. (If you don’t know what such isolation is, or why you need it, then either you should, or you will.)
The latest entries in the IGBT driver arena are devices from Avago Technologies, providing 1A, 3A, and 4A maximum output drive depending on model. The ACPL-P343/W343 has Iout min/max of 3/4 A, respectively, suitable for 1200V/200A IGBTs; the ACPL-P341/W341 has 2.5/3 A min/max ratings for 1200V/100A IGBTs; and the ACPL-P340/W340 is rated at 0.8/1A output drive min/max for 1200V/50A IGBTs.
In contrast to previous devices which use bipolar transistors for their output stage, these drivers use CMOS/DMOS processes, thus yielding the higher density and lower-power consumption of CMOS with the higher current drive and speed of bipolar technology. Target applications include industrial inverters, induction cookers, brushless DC motors, and home appliances, to cite just a few.
[If you are worried by the negative "reputation" that optocouplers have for short life due to LED degradation, Avago says these devices are intended for long-term installations and designed for 25-year viable lifetime; but old reputations take a long time to change.]
The ACPL-P34x and ACPL-W34x series has these key attributes:
- Rail-to-rail output for reliable IGBT operation, lower system power budget, and compatibility with bootstrap power supply operation
- Short propagation delay (200 ns maximum) and propagation delay difference (100 ns maximum) to reduce dead time and improve system efficiency
- Low ICC supply current for lower system-power budget, also suitable for bootstrap power-supply operation, which reduces the amount of isolated power supply needed.
- High common-mode noise rejection of at least 35 kV/μsec at VCM of 1.5 kV, to minimize erroneous driving in noisy environments
- High insulation voltage and worldwide safety approval for reinforced insulation safety approval at equipment level; drivers feature 8 mm creepage and clearance dimensions are compliant to UL 1577 and CSA safety requirements for 5000 VRMS/1 minute performance, as well as IEC/EN/DIN 60747-5-2 specifications
Other features include undervoltage lockout (UVLO) detection with hysteresis, and quiescent supply current (Icc) under 3 mA (about half of previous designs). The drivers are housed in a "stretched" SO-6 package, which is 40%-50% smaller than the DIP8 package, yielding space and cost savings.
Pricing and availability: The Avago IGBT gate-drove optocouplers are priced at approximately $1.30 each n 10k quantities. They are available now.
For more information: contact Avago at http://www.avagotech.com/optocouplers .