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Photocouplers tout IGBT protection, high-speed switching

Posted: 04 Feb 2013 ?? ?Print Version ?Bookmark and Share

Keywords:Renesas Electronics? photocoupler? PS9332L? PS9332L2? GaAlA?

Renesas Electronics Corp. has uncloaked a pair of photocouplers with an integrated insulated-gate bipolar transistor (IGBT) protection function geared for applications that include industrial machinery and solar power systems. The PS9332L and PS9332L2 feature an integrated active Miller clamp circuit to prevent IGBT malfunction, world-top-class high-speed switching among IGBT drive photocouplers, compact 8-pin SDIP (shrink dual inline package) and guaranteed high-temperature operation, indicated the company.

Aimed at gate drive of IGBT devices used in inverter circuits for motor control, the PS9332L and PS9332L2 are IGBT drive photocouplers consisting of a gallium-aluminium-arsenide (GaAlAs) LED, photo detector IC and an IGBT protection circuit. They are designed to drive the gate of an IGBT device while at the same time providing an integrated protection function to prevent destruction due to malfunction of the IGBT, Renesas noted.

When the IGBT connected to the photocoupler turns off, current flow (Miller current) between the collector and gate can cause a gate voltage, resulting in malfunction. The integrated active Miller clamp circuit shortens the gate charge to ground, suppressing any rise in the gate voltage and preventing malfunction. Integrating the protection circuit into the photocoupler simplifies system design and enables the system to be more compact overall.

The photo detector IC uses Renesas' exclusive BiCMOS process, resulting in low parasitic capacitance, shorter delay time (tPHL, tPLH ? 200ns, 20 per cent less than comparable earlier products), and low current consumption by the circuit (Icc ? 2.5mA), detailed the company. This makes it possible to build inverter control circuits that are more precise and have lower power consumption. In addition, the circuit's low current consumption enables a more compact power supply for the system driving the IGBTs.

Although it now includes an integrated active Miller clamp function, the size of the photo detector chip is equivalent to that of comparable earlier products, allowing a compact 8-pin SDIP package. This provides a 40 per cent reduction in mounting area compared with an 8-pin DIP, allowing customers to build more compact systems, the company boasted.

The materials have been improved to allow operation at high temperatures, for a maximum operating ambient temperature of 125C. This simplifies the thermal design of systems in hot environments.

Renesas believes the PS9332L and PS9332L2 will simplify development of and allow greater compactness in inverter products. Using the products in combination with Renesas' IGBT can reduce dead time in switching by about 10 per cent (compared with conventional Renesas products) and improve power efficiency. Also, Renesas expands support of customers' product development with reference boards for devices such as power conditioners and inverters as kit solution with MCUs.

Samples of the PS9332L and PS9332L2 will start in February 2013, priced at $2 per unit. The package is available with two lead frame options. The PS9332L offers 7mm outer creepage, whereas the PS9332L2 offers 8mm.

Mass production of the PS9332L and PS9332L2 is scheduled to begin around June 2013 and is expected to reach a scale of 1,000,000 units per month in October 2013.

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