SGM3124 Datasheet, PDF (6/17 Pages) SG Micro Corp – White LED Charge Pump Current Source with PWM Brightness Control

SGM3124
White LED Charge Pump Current
Source with PWM Brightness Control
TYPICAL PERFORMANCE CHARACTERISTICS
Table of Graphs
FIGURE
1
Efficiency (η)
2
LED Current, I_LED
3
Switching Frequency (f_S)
vs Input voltage (ILED = 25mA, 20mA, 15mA, 10mA, 5mA per LED), EN2 = EN1 = 1
The curve with higher efficiency is for Input voltage from high to low.
vs Duty cycle on PWM (ILED_MAX set to 20mA)
For f = 32kHz, and f = 1kHz, DC = 1% to 100%, V_IN = 3.6V.
vs Free-Air Temperature (T_A = -40℃ to 85℃, V_IN = 3.6V)
4
Quiescent Current (IQ)
vs Input voltage (T_A = 25℃) (measured with I_D1 = 5mA)
5
6
7, 8
9, 10
LED Current Regulation vs Input voltage 3 × 20mA
Maximum Output Current
from Charge Pump Stage
Dimming Response
Startup Timing
vs Input voltage (TA = 25℃)
PWM signal and current at D1 vs time on scope
f = 32kHz and f = 1kHz, V_IN = 3.6V, duty cycle = 50%, EN1 = EN2 = PWM
VIN = 3.6V, 3 × 20mA, EN1 = EN2 = 00 changed to EN2 = EN1 = 11
11
Input and Output Ripple
VIN = 3.6V, 3 × 20mA, EN1 = EN2 = 1
12
Line Transient Response
V_IN and ID1 vs time on scope, LED current at D1 with
VIN = 4.2V to 3.6V to 4.2V with EN2 = EN1 = 11, 3 × 20mA
SG Micro Corp
www.sg-micro.com
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