LD7890

4

Leadtrend Technology Corporation

www.leadtrend.com.tw

LD7890-DS-01 November, 2013

Pin Descriptions

PIN

NAME

FUNCTION

1

VIN

Power Input pin. Bypass it with a ceramic capacitor of 1

F or greater and

place it close around VIN pin.

2

OVP

Over-voltage protection and Output short protection.

3

EN

Chip enable pin, with internal 950K

 pull-down resistance.

4

RT

To set the resistor for operation frequency.

5

COMP

Compensation circuit for Boost topology.

6

PARL

Multi-chip parallel operation pin.

7,10,13,16

SENSE x

LED Current sense input pin. Connect it to GND through a sense resistor to

regulate to 0.4V. The LED current is programmable according to the equation:

8,11,14,17

Gate x

Gate pin, connection to external current source MOSFET. It sends a drive

signal to the external MOSFET to regulate the LED current.

9,12,1518

FB x

Detection pin for minimal voltage of LED light bar. The Boost Controller loop

would select minimal LED Drain pin voltage to regulate output voltage and

detect LED status. The reference voltage for FB pin is 0.8V.

19

STATUS

This pin is open drain output and indicates LED fault operation. Connector

resistor > 50K

Ω.

20

LOSC

Low frequency dimming frequency setting pin.

21

DIM

PWM or DC signal for duty cycle of dimming control signal, with internal pull

down 950K

 Resistance.

22

CS

Current sensing pin for power MOSFET, with threshold voltage of 0.5V and

LEB time of 330nS.

23

GND

IC ground.

24

DRV

Power MOSFET Driver, supplying output voltage level up to 10V.