LD8116QLGL datasheet(11/13 Pages) LEADTREND

11 / 13 page

LD8116QL

07/15/2020

Leadtrend Technology Corporation

www.leadtrend.com.tw

LD8116QL-DS-00 July 2020

Potentiometer Dimming

When DIM pin has connected a potentiometer to GND,

bias current source of DIM pin is pass thought this

potentiometer then cause a DC voltage potential on DIM

pin, LD8116QL will transfer to PWM signal on OUT pin.

This frequency of OUT pin is 1.5kHz around.

Dimming Off Performance

When the DC input signal of DIM pin is up to 1.42V,typ.,

PWM signal output of OUT pin is 9.5% duty cycle. But

the DC input signal of DIM pin is lower to 1.26VDC, the

OUT pin is pull low to GND. If dimmer signal on DIM pin

is PWM condition, dimming off duty cycle is under

2%,typ..Then IC recover operation is higher than 4%,typ..

Internal Over Temperature Protection

When internal over temperature protection is occur

(135

C typ.). The OUT pin of LD8116QL is open drain

and auto-recovery after thermal down to normal

operating temperature.

Optocouplers Selection Guide

LD8116QL converts an analog dimming signal into a

PWM waveform. In the majority of applications the

dimming signal needs to be isolated from the rest of the

application and an optocoupler is used to implement

either functional or reinforced isolation. Optocouplers

are an excellent choice since they are very cost effective

but nevertheless able to comply with virtually all safety

standards. The most common and cost effective

optocouplers are four-pin devices consisting of a LED

and a photosensitive BJT. With four pin devices only

collector and emitter of the BJT are connected to pins.

This limits device performance, especially switching

times, as will be discussed later. Six-pin devices having

the base of the BJT as well connected to a pin are seen

less often. With these six-pin devices bandwidth of the

transmission can be improved if necessary. Finally there

are high-speed digital couplers available that are

designed for very high data rates and offer a buffered

output with a nearly perfect PWM signal. While offering

superior

performance

high

speed

couplers

are

considerably more expensive than simple LED-BJT

couplers. There are two parameters of an optocoupler

that are most important for use with LD8116QL: the

current transfer ratio CTR and the switching times Tr

and Tf.

A typical plot of Tr and Tf vs, RL taken from the data

sheet of a widely used 4-pin optocoupler.

PCB Design Guideline

1. The bypass capacitor of VCC should be placed as

close as possible to the VCC and GND pin of IC.

2. CLPF and CDIM capacitors should be as short as

possible to GND pin (pin 2).

LD8116QLGL Datasheet(PDF) 11 Page - Leadtrend Technology

LD8116QLGL Datasheet(HTML) 11 Page - Leadtrend Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13

Datasheet Download

Link URL