Monday, September 04, 2006
HP Introduces Low-Cost, SO-16, Half-bridge Gate Drive Optocoupler for Motor-Control Applications
Low-Cost Bootstrap-Powered Optocoupler Makes Isolated Gate Drive
Affordable for Home Appliances and HVAC Motor Drives
Hewlett-Packard Company today announced a 0.4-amp-output half-bridge gate drive optocoupler designed specifically for low-power (up to 25A) motor-control-inverter applications, such as air conditioners and washing machines using inverters based on insulated-gate bipolar transistor (IGBTs). The voltage and current provided by the HCPL-314J also makes it suitable for low-power industrial applications.
Motor drives with electronic speed and power control -- such as variable-frequency drives (VFDs) -- enable pumps, blowers and fans to accommodate fluctuating demand, running at a lower speed when power demand is lower, thus drawing less energy while still meeting the appliance needs. Single-speed drives start motors abruptly, subjecting motors to high torque and current surges of up to 10 times the full-load current. VFDs, on the other hand, offer a "soft-start" capability, gradually ramping a motor up to operating speed. This soft-start capability lessens mechanical and electrical stress on the motor system, and can reduce maintenance and repair costs and extend motor life.
These benefits apply to home-heating and air-conditioning systems and to appliances such as washers, dryers and dishwashers. Appliance manufacturers are using the technology to produce better-performing, more-energy-efficient appliances.
The HCPL-314J features very low power consumption (operating current less than 3mA), making it possible to power the optocoupler using a bootstrap technique, which eliminates the need for costly, isolated power.
Because the HCPL-314J features two channels integrated in one surface-mountable, industry-standard SOIC-16 package, it requires less board space -- up to 50 percent less -- than conventional, single-channel 8-pin DIP optocouplers.
Propagation delays between channels are matched to within 0.7 microseconds, allowing designers to minimize the "dead time" in an inverter and maximize its efficiency.
The HCPL-314J optocoupler is an excellent alternative to high-voltage integrated circuits (HVICs) and provides a low-cost way to drive an insulated-gate bipolar transistor (IGBT). Unlike HVICs, the HCPL-314J, with its superior galvanic isolation, supports a microcontroller that is fully isolated from the high-voltage portion of the inverter, protecting the user from shock hazards.
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