beautypg.com

Derating option for 2 to 8 white leds, Typical operating characteristics – Rainbow Electronics MAX8596Z User Manual

Page 4

background image

MAX8595Z/MAX8596Z

High-Efficiency, 32V Step-Up Converters
with T

A

Derating Option for 2 to 8 White LEDs

4

_______________________________________________________________________________________

Typical Operating Characteristics

(Circuit of Figure 1, V

IN

= 3.6V, I

LED

= 25mA, L = 22µH, C

IN

= 2.2µF, C

OUT

= 0.1µF, C

COMP

= 0.1µF, R

SENSE

= 13

Ω, 4 LEDs,

T

A

= +25°C, unless otherwise noted.)

EFFICIENCY

vs. INPUT VOLTAGE

MAX8595Z toc01

INPUT VOLTAGE (V)

EFFICIENCY (%)

5

4

3

55

60

65

70

75

80

85

90

95

100

50

2

6

3 LEDs

4 LEDs

6 LEDs

8 LEDs

EFFICIENCY

vs. LED CURRENT

MAX8595Z toc02

LED CURRENT (mA)

EFFICIENCY (%)

25

20

15

10

5

65

70

75

80

85

90

60

0

30

3 LEDs

6 LEDs

8 LEDs

LED CURRENT

vs. DIRECT-PWM DIMMING

MAX8595Z toc03

DUTY CYCLE (%)

LED CURRENT (mA)

80

60

40

20

5

10

15

20

25

30

0

0

100

LED CURRENT

vs. AMBIENT TEMPERATURE

MAX8595Z toc04

TEMPERATURE (

°C)

LED CURRENT (mA)

80

60

20

40

0

-20

10

12

14

16

18

20

22

24

26

8

-40

100

MAX8596,
I

LED

= 25mA AT T

A

= +25

°C

MAX8595,
I

LED

= 15mA

SWITCHING WAVEFORMS

MAX8595Z toc05

500ns/div

V

IN

20mV/div
AC-COUPLED

200mV/div
AC-COUPLED

100mA/div

10V/div

V

LX

V

OUT

I

L

SOFT-START AND SHUTDOWN RESPONSE

MAX8595Z toc06

20ms/div

V

CTRL

2V/div

0

0

0

0

40mA/div

10V/div

100mA/div

I

IN

I

LED

V

OUT