SC4505
SC4505 is High Efficiency Boost Converter manufactured by SEMTECH.
Description
The SC4505 is a high-frequency PWM current-mode stepup switching regulator with an integrated 2A power transistor. Its high switching frequency (1MHz) allows the use of tiny surface-mount external passive ponents. The internal switch is rated at 36V which makes the converter ideal for multiple LED series operation with optimal current matching. Two programmable independent current source structure allows dual panel LED backlight and flash operation. .. The operating frequency of the SC4505 is set at 1MHz. The selected operating frequency gives the SC4505 design flexibility for size, cost and efficiency optimization. The SC4505 is available in thermally enhanced 16-pin MLPQ package (3x3x0.9mm) with embedded over temperature protection.
Features
Two independent current sources for dual LED strands with optimal current/light matching. Backlight up to 75m A, Flash up to 125m A Wide input range from 2.6V to 12V Adaptive output voltage up to 28V with OVP protection against open circuit conditions Low shutdown current (<1µA ) Internal Flash/Torch mode with flash timeout to protect LEDs 1MHz Fixed Frequency Current-Mode Control Internal 2A current limit for driving large numbers of LEDs Supports PWM Dimming from 50Hz to 50k Hz Internal undervoltage lockout Small, low profile, thermally enhanced 16-MLPQ package is fully WEEE and Ro HS pliant
Applications
White LED power supplies Flat screen LCD bias supplies TFT bias supplies Dual panel Handset/Liquid Crystal Display Monitor Portable media players Digital video cameras Digital still cameras
Boost Converter Efficiency vs Input Voltage (2 String of 3 LEDs @30m A) 87
Typical Application Circuit
VIN: 2.6V ~ 6.0V
L1 2 IHLP-2525CZ-01-1R5-M-01
LED: SML-LX0603UWD
D1 1 D2 LED D3 LED 10BQ015 C1
C2 PGND 2.2u
2.2u F
85 Efficiency (%)
C5 12n (Optional) D5 LED
C3 0.33u F
SC4505 16 15 14 13 12 11 VIN FTO FL_TRB EN_FL EN_BL IO1SET IO2SET AGND PGND PGND SW SW VO IO2 IO1 P 1 2 3 4 5 6 7 8...
