Contents

AN4376

2/37

DocID025380 Rev 1

Contents

1

Theory of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2

EVLHVLED815W10A - main characteristics and circuit description . . 8

2.1

LED current definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.2

LED current ripple definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.3

DMG pin and OVP setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.4

External compensation network of the voltage loop . . . . . . . . . . . . . . . . . 10

2.5

Power factor corrector function and ILED pin modulation with the input

mains voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.6

High-voltage start-up generator and VCC capacitor . . . . . . . . . . . . . . . . .11

3

Electrical diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

4

Bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

5

Component layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

6

Measurement results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

6.1

LED driver performance at nominal load 70 VDC - 140 mA . . . . . . . . . . . 16

6.2

Line regulation at nominal load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

6.3

Power factor at nominal load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

6.4

Total harmonic distortion (THD) at nominal load . . . . . . . . . . . . . . . . . . . 17

6.5

Driver efficiency at nominal load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

6.6

LED driver performance varying the number of LEDs . . . . . . . . . . . . . . . 18

6.7

Line regulation at different LED load number . . . . . . . . . . . . . . . . . . . . . . 19

6.8

Power factor at different LED load number . . . . . . . . . . . . . . . . . . . . . . . 20

6.9

Total harmonic distortion (THD) at different LED load number . . . . . . . . . 21

6.10

LED driver efficiency at different LED load number . . . . . . . . . . . . . . . . . 22