Linear Technology LT3956 Series Скачать руководство пользователя страница 17

LT3956

3956f

Typical applicaTions

Buck-Boost Mode LED Driver

LT3956

L1

68µH

GND

V

C

INTV

CC

EN/UVLO

FB

PGND

V

REF

ISP

1M

0.1µF

V

IN

9V TO

45V

V

IN

V

IN

V

OUT

L1: COILCRAFT MSS1038-683

D1: ON SEMICONDUCTOR MBRS3100T3

M1: ZETEX ZXM6IP03F

Q1: ZETEX FMMT493

187k

35.7k

300kHz

3.4k

10nF

4.7µF

CTRL

750Ω

1k

Q1

M1

680mΩ

619k

10k

D1

4.7µF

35V

3956 TA03a

VMODE

PWM
SS
RT

ISN

PWMOUT

C1

4.7µF

1µF

100V

24V

LED STRING

350mA

100k

INTV

CC

INTV

CC

V

IN

SW

Efficiency vs V

IN

V

IN

 (V)

0

10

80

EFFICIENCY (%)

84

88

92

96

100

30

40

3956

TA03b

20

50

28V

IN 

/0V to 28V SEPIC SuperCap Charger with Input Current Limit

V

IN

LT3956

L1A

33µH

1:1

GND

V

C

INTV

CC

INTV

CC

EN/UVLO

SW

V

REF

ISP

10k

1µF

10nF

V

IN

28V

≤ 1.2A

V

OUT

0V TO 28V

L1: WÜRTH ELEKTRONIK 744871330

D1: ON SEMI MBRS36OT

Q1: MMBTA42

C1, C3, C4: TAIYO-YUDEN GMK 3I6BJ106

28.7k

375kHz

C3

10µF

PGND

L1B

C2

4.7µF

CTRL

30.1k

1M

D1

C4

10µF

3956 TA04a

VMODE

PWMOUT

PWM

SS

RT

ISN

FB

40.2k

1M

2k

59k

25k

536k

14k

C1

10µF

Q1

200mΩ

Input and Output Current

vs Output Voltage

V

OUT

 (V)

0

0

INPUT/OUTPUT CURRENT (A)

0.5

1.0

1.5

2.0

3.0

5

10

15

20

3956 TA04b

25

30

2.5

INPUT

OUTPUT

Содержание LT3956 Series

Страница 1: ...imming capability 94 Efficient 25W White LED Headlamp Driver n 3000 1 True Color PWMTM Dimming n Wide Input Voltage Range 4 5V to 80V n Output Voltage Up to 80V n Internal 3 3A 84V Switch n Constant C...

Страница 2: ...ww linear com leadfree This product is only offered in trays For more information go to http www linear com packaging PARAMETER CONDITIONS MIN TYP MAX UNITS VIN Minimum Operating Voltage VIN Tied to I...

Страница 3: ...se Amplifier Input Common Mode Range VISN 2 9 80 V ISP ISN Short Circuit Threshold V ISP ISN ISN 0V 300 335 370 mV ISP ISN Short Circuit Fault Sensing Common Mode Range VISN 0 3 V ISP ISN Input Bias C...

Страница 4: ...m Ratings may cause permanent damage to the device Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime Note 2 The LT3956E is guaranteed to...

Страница 5: ...125 1 96 1 98 2 00 2 02 2 04 1 97 1 99 2 01 2 03 VIN V 1 96 V REF V 1 98 2 00 2 02 2 04 1 97 1 99 2 01 2 03 3956 G06 0 20 40 80 60 3956 G08 SWITCHING FREQUENCY kHz TEMPERATURE C 50 0 50 75 25 25 100 1...

Страница 6: ...SWITCHING 3956 G15 INTV CC V TEMPERATURE C 50 0 50 75 25 25 100 125 7 0 7 2 7 4 7 1 7 3 DUTY CYCLE 2 5 SW PIN CURRENT LIMIT A 3 5 4 5 3 0 4 0 3956 G16 0 25 50 75 100 FB VOLTAGE V 3956 G17 1 2 1 22 1 2...

Страница 7: ...ons from a linear function to a constant value reaching 98 of full scale value by VCTRL 1 1V Connect CTRL to VREF for the 250mV default threshold Do not leave this pin open NC NoInternalConnection The...

Страница 8: ...or If not used connect to INTVCC VMODE An open collector pull down on VMODE asserts if the FB input is greater than the FB regulation threshold minus 50mV typical To function the pin requires an exter...

Страница 9: ...llowed to exceed the current limit threshold of 3 9A typical If the SW pin exceeds the current limit threshold the SR latch is reset regardless of the output state of the PWM compara tor Likewise at a...

Страница 10: ...t Programming The LED current is programmed by placing an appropri ate value current sense resistor RLED between the ISP and ISN pins Typically sensing of the current should be done at the top of the...

Страница 11: ...T R4 3956 F03 R3 LED ARRAY RLED Figure 3 Feedback Resistor Connection for Buck Mode or Buck Boost Mode LED Driver Programming Output Voltage Constant Voltage Regulation or Open LED Overvoltage Thresho...

Страница 12: ...alue see Table 1 An external resistor from the RT pin to GND is required do not leave this pin open Table 1 Switching Frequency vs RT Value fOSC kHz RT k 1000 10 900 11 8 800 13 700 15 4 600 17 8 500...

Страница 13: ...to have occurred Input Capacitor Selection Theinputcapacitorsuppliesthetransientinputcurrentfor the power inductor of the converter and must be placed andsizedaccordingtothetransientcurrentrequirement...

Страница 14: ...ent Duringstart upwithEN UVLO charging of the soft start capacitor is enabled after the first PWM high period Schottky Rectifier Selection The power Schottky diode conducts current during the interval...

Страница 15: ...ane under the switching node to eliminate interplane coupling to sensitive signals The lengths of the high dI dt traces 1 from the switch node through the switch to PGND and 2 from the switch node thr...

Страница 16: ...F s 5 CC 4 7nF VIN 6V TO 60V 80V TRANSIENT CSS 47nF R2 100k RC 20k RT 28 7k 375kHz CVCC 4 7 F 40 2k CTRL R4 16 2k R3 1M RS 0 68 370mA M1 INTVCC 3956 TA02a VMODE PWM SS RT ISN FB PWMOUT M1 VISHAY SILI...

Страница 17: ...iency vs VIN VIN V 0 10 80 EFFICIENCY 84 88 92 96 100 30 40 3956 TA03b 20 50 28VIN 0V to 28V SEPIC SuperCap Charger with Input Current Limit VIN LT3956 L1A 33 H 1 1 GND VC INTVCC INTVCC EN UVLO SW VRE...

Страница 18: ...0 EFFICIENCY 84 88 92 96 100 30 40 3956 TA05b 20 50 Typical Applications Efficiency vs VIN 90W Buck Mode LED Driver 80VIN 60VOUT VIN VIN LT3956 GND VC INTVCC VREF INTVCC EN UVLO SW ISP 100k INTVCC 1M...

Страница 19: ...CE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE PIN 1 TOP MARK NOTE 6 0 40 p 0 10 1 36 35 30 31 32 33 34 28 20 21 23 24 25 27 2 3 4 6 8 9 10 12 13 14 15 16 17 BOTTOM VIEW EXPOSED PAD 2 00 REF 1...

Страница 20: ...n LED Driver VIN 4V to 36V VOUT MAX 13 5V True Color PWM Dimming 3000 1 ISD 1 A TSSOP20E Package LT3476 Quad Output 1 5A 36V 2MHz High Current LED Driver with 1000 1 Dimming VIN 2 8V to 16V VOUT MAX 3...

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