Power Electronics

High-Voltage Single-Ended Converter

Expanding its power management portfolio, National Semiconductor Corp.’s new high-voltage, single-ended converter contains all the functions required to implement control, drive and regulation in flyback and forward power supplies.

Packaged in a tiny (4 mm × 4 mm), thermally enhanced chip-scale package, this device integrates a 100-V start-up bias regulator, a current-mode PWM controller, 1.5-A power MOSFET driver and precision high-frequency control circuitry, making it a compact and efficient solution for many Power-over-Ethernet (PoE) powered device (PD) applications. It’s also an ideal bias supply controller for 42-V automotive, 36-V industrial power bus and high-availability distributed power systems in 48-V communications equipment, such as central office switches, routers and DSL access multiplexers.

National’s LM5020 is offered as a high-voltage (up to 100 V) single-ended converter controller that will complement the recently launched LM5030 push-pull controller.

The high-speed LM5020 controller provides total propagation delays less than 100 ns and a 1-MHz-capable oscillator that is programmed with a single resistor. The level of integration and innovative technology in National’s LM5020 differentiates it from competitors’ products:

  • Wide-range, 15-V to 100-V, start-up bias regulator

  • High-speed, 1.5-A peak power MOSFET driver

  • User-programmable line undervoltage lockout (UVLO) with hysteresis

  • Tiny, 10-pin MSOP or 10-pin thermally enhanced LLP chip-scale package

Additional features of the LM5020 include error amplifier, precision reference, cycle-by-cycle current limit, internal slope compensation, programmable soft-start, oscillator synchronization capability and thermal shutdown. Customers will benefit from reduced component count, high-speed performance, elimination of the external start-up regulator, power on sequencing, minimized start-up surge currents and the capability to synchronize the oscillator while eliminating interference.

For more information, visit www.national.com.

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