MCP1650 datasheet(17/20 Pages) MICROCHIP

17 / 20 page

www.microchip.com/lighting

LED Lighting Solutions Design Guide

LED Lighting Solutions

Logic Output Temperature Sensors

Low cost temperature

sensing devices such

as the TC6501 and

TC6502 (offered in

SOT-23 packages) can be

conveniently placed near

power LED(s) to obtain a

more accurate temperature

monitoring and provide a

logic output fault signal.

The fault signal will be activated as soon as a factory-

programmed temperature threshold is reached. Temperature

threshold values can be selected in increments of 20°C as

indicated in the following table.

TC6501/TC6502 Logic Output Temperature Sensors

Device

Temperature

Threshold (°C)

TC6501P045VCT

TC6501P065VCT

TC6501P075VCT

TC6501P095VCT

TC6501P0105VCT

105

TC6501P0115VCT

115

TC6501P0120VCT

120

TC6501P0125VCT

125

Resistor-Programmable Temperature Switches

The MCP9509/10 devices are programmable logic output

temperature switches. The temperature switch threshold can

be programmed with a single external resistor, which provides

high design flexibility and simplicity. In addition, this family

of devices provide user programmable features such as 2°C

and 10°C (typical) switch hysteresis and output structure

configuration. The MCP9509 provides an open drain output,

whereas the MCP9510 is offered in three different user

selectable output configurations: Active-low/Active-high

push pull and Active-Low Open-Drain output with an internal

100 kΩ pull-up resistor.

The MCP9509/10 operate from 2.7V to 5.5V. This family is

capable of triggering for temperatures -40°C to +125°C with

high accuracy.

MCP9509/10 Resistor-Programmable

Temperature Switches

Device

Temperature Threshold (°C)

MCP9509CT-E/OT

-40ºC to +125ºC (Falling Hot to Cold)

MCP9509HT-E/OT

-40ºC to +125ºC (Rising Cold to Hot)

MCP9510CT-E/CH

-40ºC to +125ºC (Falling Hot to Cold)

MCP9510HT-E/CH

-40ºC to +125ºC (Rising Cold to Hot)

TOVER

TC6501

TC6502

GND

VCC

HYST

GND

TC6501

TC6502

Temperature Sensing Solutions for

Power LED Applications

Every light source has a specific energy efficiency. A certain

portion of the energy supplied to it is wasted in the form of

heat. One of the fundamental differences between Power

LED technology and other traditional sources of light is in

the way this heat is transferred. In fact, LEDs are particularly

good at producing a radiation with very narrow range of

frequencies typically designed to produce a specific color

in the visible spectrum. There is very little infrared (heat)

radiation produced. All the heat produced by the light

source has to be transferred instead by contact. Packaging

technology plays an important role in facilitating the heat

transfer from the LED, but an accurate thermal analysis

of the entire lighting application (total thermal resistance

from junction to ambient) is required to guarantee that

the maximum temperature of the junction is not exceeded

during operation. In particular, white LEDs employ phosphor

materials to convert the monochromatic light emitted into a

wider spectrum, to produce a “white” color. The phosphors

are even more sensitive to temperature and can be easily

damaged if overheated.

Before the LED junction reaches the maximum operating

junction temperature (typically 125°C) the temperature

increase will have negative impact on a number of LED

characteristics including efficiency, light intensity, lifetime

and color.

While the safe way to design a power LED application is to

provide a low temperature resistance path to a heat sink

that is dimensioned for the worst possible environmental

and usage conditions, this might not always be possible

for physical or cost constraints. For this reason driver

ICs used in LED applications (such as the MCP1630 and

MCP1650) often incorporate an over-temperature protection,

performing what is substantially a device shutdown when

the temperature rises above a given threshold. While this is

effective to protect the device from reaching temperatures

that could damage the LED (or the phosphor layer for white

LED applications), the driver IC is not always guaranteed

to be placed close to the emitting device(s). If the LEDs

are arranged in modules, separate from the driving circuit,

comprising several emitters connected in series or parallel,

the temperature sensed by the driver could be considerably

different from the actual module emitter’s junctions.

MCP1650 Datasheet(PDF) 17 Page - Microchip Technology

MCP1650 Datasheet(HTML) 17 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Datasheet Download

Link URL