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National intros 'first' 6-100V current-mode buck controller

Posted: 01 Mar 2007 ?? ?Print Version ?Bookmark and Share

Keywords:power management? buck controller? PWM? National? MOSFET?

National Semiconductor Corp. said it has introduced the industry's first 6V to 100V current-mode buck controller for use in telecommunications, automotive and industrial control applications.

The LM5116 is suitable for step-down regulator applications from a high voltage or widely varying input supply. The current mode control using National's patented emulated current-mode (ECM) technology reduces noise sensitivity of the pulse-width modulation (PWM) circuit, and enables reliable control of very small duty cycles necessary in high input voltage applications, said the company. Additional features include thermal shutdown, programmable soft-start, frequency synchronization, cycle-by-cycle current limit and adjustable line undervoltage lockout (UVLO).

Ultrawide input
The LM5116 offers an ultrawide input range up to 100V, with a programmable output range from 1.215V to 80V. The reduced noise sensitivity of the PWM control circuit allows reliable operation with very small duty cycles necessary in high input voltage applications. The emulated current ramp enables the LM5116 to exceed a 20:1 Vin:Vout step-down ratio when operating at 500kHz. The operating frequency is user-programmable up to 1MHz with the capability to synchronize switching to an external clock signal.

In addition, a low quiescent-current sleep mode disables the controller and consumes only 10?A of total input current for minimal off-state drain in battery-powered applications. A user-selectable diode emulation mode enables discontinuous inductor current operation at light load conditions for improved efficiency. Controlled start up into a pre-biased load is achieved by gradually disabling the diode emulation of the synchronous MOSFET. The programmable soft-start, input UVLO and voltage tracking features further enhance the system designer's control of the turn-on transition, said the company.

The LM5116 is available in a power-enhanced TSSOP-20 package featuring an exposed die attach pad to aid in thermal dissipation.

The LM5116 in currently available and priced at $3.25 in quantities of 1,000.

- Gina Roos

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Related Datasheets
Part Number Description Category
? LM5116 Wide Range Synchronous Buck Controller from the PowerWise? Family ICs, Interface



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