Gate drivers

National Semiconductor’s latest additions to its family of high-voltage power control ICs are targeted at developers of DC-DC power supplies.

The dual-channel LM5111 and single-channel LM5112 are gate drivers that are suitable for driving large power MOSFETs used in AC-DC and DC-DC converters, motor drives and industrial control systems.

The LM5112, available in a 3 mm by 3 mm LLP-6 package, also enables the design of DC-DC converters when used as part of a chipset with National’s LM5000 family of pulse width modulation (PWM) controllers and LM510x half-bridge drivers.

Designed using National’s high-voltage Analog-BiCMOS-DMOS (ABCD) technology, the LM5112’s compound output driver stage includes MOS and bipolar transistors operating in parallel. This combination can sink more than 7 Apk from capacitive loads, driving large power MOSFETs at frequencies up to 1 MHz. A major benefit of the unique compound drive stage is that it offers users more reliable operation by reducing drive current variations during supply voltage and temperature changes.

The LM5112 also provides separate ground and reference pins for the input and output stages to support split-supply gate drive configurations. Because its dual-logic interface accepts either inverting or non-inverting signals, the LM5112 is flexible enough to interface with most power controllers and microprocessors on the market today.

The LM5111 offers two full 5 Apk drivers in a SOIC-8 package that can directly replace many older CMOS gate drive solutions, while offering an improved peak output current of 5 Apk compared to 2 Apk, as well as higher-efficiency operation.

The LM5111 also allows the normally separate 5 Apk drive channels to be tied in parallel with their inputs and outputs connected, doubling the output drive current capacity to 10 Apk for driving extremely large power MOSFETs at speeds up to 1 MHz. It is available in three different input signal options: the two channels can be non-inverting, inverting or a combination of the twoAvailable today, the LM5111 is priced at $0.65 and the LM5112 is priced at $0.55 each in 1K volumes.

More information about the LM5111 is available <link>here=http://www.national.com/pf/LM/LM5111.html</link> while more details on the LM5112 can be found <link>here= http://www.national.com/pf/LM/LM5112.html</link>.