Applied to high power LED PCB

The current application with high power LED heat dissipation of PCB there are three kinds of ordinary double coated copper ( FR4) , aluminum alloy coated copper ( MCPCB) PCB, flexible film with adhesive on the aluminum alloy board PCB.

MCPCB structure as shown in figure 7. The thickness of each layer dimensions as shown in table 3.

figure 7 MCPCB structure of the cooling effect and the copper layer and metal layer thickness, such as degree of size and the conductivity of the insulating medium. Generally USES 35 microns copper layer and 1. 5 mm aluminum alloy MCPCB. Flexible PCB adhesive in the structure of aluminum alloy plate as shown in figure 8. Generally used in each layer thickness dimension as shown in table 4. 1 ~ 3 w LED star using this structure. Use high thermal conductivity of MCPCB has the best heat dissipation performance, but the price is more expensive.

figure 8 heat dissipation layer structure calculation example here USES the

the NICHIA company measurement of TC of part of the instance of data as an example of calculation. Condition known as follows LED3W white LED, model MCCW022, RJC = 16 ℃ / W. K type thermocouple thermometer head welding heat mat. Double coated copper (PCB test board 40×40毫米) t = 1。 Area of 1180 was 6 mm, welding surface copper layer on the back of the copper layer area was 1600. The LED working state IF = 500 ma, VF = 3. 97V。 According to the figure 9 with K type thermocouple thermometer to measure TC, TC = 71 ℃. Test environment temperature TA = 25 ℃.

　　1. TJ computing

TJ = RJC by PD + TC = RJC ( 如果×VF) + TC TJ = 16℃/ W ( 500mA×3. 97V)

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