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KB1365

Kingbor Technology Co.,Ltd

TEL:(86)0755-26508846 FAX:(86)0755-26509052

The KB1365 are step-down, constant-

current, high-brightness LED (HB LED) drivers. These

devices operate from a 5.5V to 40V input voltage range

and provide up to 0.5A of source and 1A of sink drive

capability to the gate of an external MOSFET. A high-

side current-sense resistor sets the output current and

a dedicated PWM dimming input (DIM) allows for a

wide range of independent pulsed dimming.

The high-side current-sensing scheme and on-board

current-setting circuitry minimize the number of exter-

nal components while delivering LED current with a

±5% accuracy, using a 1% sense resistor. See the

Functional Diagram.

Undervoltage Lockout (UVLO)

The KB1365 include a 5.0V undervoltage

below 4.5V, DRV goes low, turning off the external n-chan-

5V Regulator

DIM Input

The KB1365 allow dimming with a PWM

signal at the DIM input. A logic level below 0.6V at DIM

forces the KB1365’s DRV output low,

turning off the LED current. To turn the LED current on,

the logic level at DIM must be at least 2.8V.

Characteristics.

Current Regulator Operation

The KB1365 regulate the LED output

current using an input comparator with hysteresis

(Figure 1). As the current through the inductor ramps

up and the voltage across the sense resistor reaches

the upper threshold, the voltage at DRV goes low, turn-

ing off the external MOSFET. The MOSFET turns on

again when the inductor current ramps down through

the freewheeling diode until the voltage across the

sense resistor equals the lower threshold. Use the fol-

lowing equation to determine the operating frequency:

f

Vn V

n V

R

VV L

SW

IN

LED

LED

SENSE

IN

=

−×

×

××

∆

REV: 1.0

Setting nominal average output current with external resistor RS

The nominal average output current in the LED(s) is determined by the value of the external

The table below gives values of nominal average output current for several preferred values of

Nominal average

output current (mA)

0.1

2000

0.57

350

0.2

1000

Detailed Description

Applications Information

Inductor selection

Recommended inductor values for the KB1365 are in the range 22 H to 220 H(100 H Typ.).

()

0.07

0.2

0.4

Rs selection

0805:0.3R//0.3R//0.3R

0805:0.1R+0.1R

0805:1R//2.2R//3.6R