SC4501 查看數據表（PDF） - Semtech Corporation

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SC4501

2Amp, 2MHz Step-Up Switching Regulator with Soft-Start

Semtech Corporation 

SC4501

POWER MANAGEMENT

Typical Application Circuits

2.6 - 4.2V

0.7A (FLASH)

0.2A (TORCH)

L1

2.2µH

SUMIDA

CR43

1-CELL

LI-ION

C1

2.2µF

6

5

OFF ON IN

3

SHDN

SW

FB 2

SC4501

8 SS

COMP 1

GND ROSC

C3

4

10nF

7

R4

8.06K

- 3.4V to 3.8V +

R6

D2

0.1Ω

LXCL-PWF1

R1

698

D1

10BQ015

1/2

LM358

Q1

MMBT 3904T

C5

0.1µF

C4

R5

10nF 10K

R6

17.4K

R2

43.2K

M1

MMBF2201NT 1

C2

4.7µF

TORCH FLASH

Figure 14(a). 1.4MHz LuxeonTM Flash White LED Driver for Camera Phones

CH1

CH2

CH3

CH4

VIN = 2.6V

CH1

CH2

CH3

CH4

VIN = 4.2V

4ms/div

(b)

4ms/div

(c)

CH1 : Torch/Flash Control Voltage, 5V/div

CH2 : FB Pin Voltage, 1V/div

CH3 : LED Current, 0.5A/div

CH4 : Inductor Current, 1A/div

Figure 14(b) and 14(c). Photo Flash LED Current is Switched Between Torch Mode (0.2A) and Flash Mode (0.7A).

Higher LED Current (>0.7A) in Flash Mode is Possible with Fresh Battery.

© 2005 Semtech Corp.

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