LB1847 datasheet(13/16 Pages) SANYO

13 / 16 page

LB1847

No. 5982-13/16

Sample Application Circuit

Notes on Usage

1. External diodes

Because this IC uses top-side transistor switching in SLOW DECAY mode and dual-side transistor switching in FAST DECAY

mode, it requires external diodes between the OUT pins and ground, for the regenerative current during switching OFF. Use Schottky

barrier diodes with low VF.

2. VREF pin

Because the VREF pin serves for input of the set current reference voltage, precautions against noise must be taken. The input voltage

range is 0 to 3.0V.

3. GND pin

The ground circuit for this IC must be designed so as to allow for high-current switching. Blocks where high current flows must use

low-impedance patterns and must be removed from small-signal lines. Especially the ground connection for the sensing resistor RE

at pin E, and the ground connection for the Schottky barrier diodes should be in close proximity to the IC ground.

The capacitors between VCC and ground, and VBB and ground should be placed close to the VCC and VBB pins, respectively.

A11320

23456

789

µF

470 pF

µF

42V

0.51

Ω

0.51

Ω

15 k

Ω

15 k

Ω

1.5V

1.5V to 4.0V

SBD

Logic input

LB1847

voltage setting

LB1847 Datasheet(PDF) 13 Page - Sanyo Semicon Device