Auto Electronics

National introduces high-voltage, monolithic two-switch forward dc-dc regulator

National Semiconductor has introduced a high-voltage, monolithic two-switch forward dc-dc regulator for power supply designs in automotive and other applications. The LM5015, among the first devices of its kind, according to National, features an input voltage range from 4.25 V to 75 V and maximum switching frequency to 750 kHz. It’s said to enable easy implementation of isolated or non-isolated dc-dc converters using a minimum of external components.

The LM5015 integrates two 75 V N-channel MOSFET switches, high-side and low-side, with a minimum 1 A peak current limit, in a 14-pin TSSOP for a reduced system component count and small solution size. The two-switch forward architecture is said to reduce system losses and noise.

The LM5015 features all of the functions needed to implement efficient two-switch forward and two-switch flyback power converters with a minimum number of external components. The voltage across the MOSFETs is clamped to the input voltage, allowing the input voltage range to approach the rating of the MOSFETs. The regulator control method is based on current-mode control, providing inherent ease-of-loop compensation and line feed-forward for superior rejection of input transients.

The operating frequency of the LM5015 is set with a single resistor and is programmable up to 750 kHz. The oscillator can also be synchronized to an external clock. Additional protection features include cycle-by-cycle current limiting, thermal shutdown, undervoltage lockout and remote shutdown capability. The device’s TSSOP package features an exposed die attach pad to enhance thermal dissipation. The LM5015 is priced at $2.05 each in 1,000-unit quantities.

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