UM0971 datasheet(12/45 Pages) STMICROELECTRONICS

12 / 45 page

Board description

UM0971

12/45

Doc ID 17701 Rev 1

2.2.2

L4976 characteristics

The L4976 is a step down monolithic power switching regulator delivering 1 A at a voltage

between 3.3 V and 50 V (selected by a simple external divider). A wide input voltage range

from 8 V to 55 V and output voltages regulated from 3.3 V to 40 V cover the majority of

today's applications. Features of this new generation of DC-DC converters include pulse-by-

pulse current limit, hiccup mode for short-circuit protection, voltage feedforward regulation,

protection against feedback loop disconnection and thermal shutdown. The device is

available in plastic dual-in-line, MINIDIP 8 for standard assembly, and SO16W for SMD

assembly. It features:

●

Up to 1 A step down converter

●

Operating input voltage from 8 V to 55 V

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Precise 5.1 V reference voltage

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Output voltage adjustable from 0.5 V to 50 V

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Switching frequency adjustable up to 300 kHz

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Voltage feedforward

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Zero load current operation

●

Internal current limiting (pulse-by-pulse and hiccup mode)

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Protection against feedback disconnection

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Thermal shutdown

Figure 5.

Typical application circuit

2.2.3

Inverse polarity protection

To prevent accidental polarity inversion when supplying the STEVAL-IHM031V1 board

through connector J22, a protection circuit has been provided. It is made up of a diode and

a fuse of 6.3 A. In the case of polarity inversion occurring, the fuse F1 is permanently

damaged and needs to be replaced before the next system operation.

2.3

Gate driving

The L6387E is a high-voltage device, in the DIP-8 and SO-8 package, manufactured with

BCD “OFF-LINE” technology. It has a driver structure that enables the driving of an

independent referenced N-channel power MOSFET or IGBT. The high side (floating) section

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