ISL97672B_14 Datasheet, PDF (1/16 Pages) Intersil Corporation – 6-Channel LED Driver with Ultra Low Dimming Capability

6-Channel LED Driver with Ultra Low Dimming
Capability
ISL97672B
The ISL97672B is an integrated 6-channel power LED driver for
LCD backlight applications. ISL97672B is capable of driving
LEDs with input from 4.5V to 26.5V and maximum output up to
45V.
The ISL97672B employs an adaptive boost switching
architecture that allows Direct PWM dimming with dimming
duty cycle as low as 0.007% at 200Hz or 0.8% at 20kHz. PWM
Dimming frequency can be as high as 30kHz.
The ISL97672B employs the dynamic headroom control that
monitors the highest LED forward voltage string for output
regulation to minimize headroom voltage and power loss in a
typical multi-string operation. Typical current matching between
channels is ±0.7%.
The ISL97672B incorporates extensive protection functions
that flag whenever a fault occurs. The protections include
string-open and short-circuit detections, OVP, OTP, and an
optional output short-circuit protection with external fault
disconnect switch
The ISL97672B is offered in a compact 20 Ld QFN 3x4
package and can operate in ambient temperatures of -40°C to
+85°C.
Features
• 6 x 50mA channels
• 4.5V to 26.5V input
• 45V output max
• Adaptive boost switching architecture
• Direct PWM dimming with dimming linearity of
0.007%~100% at 200Hz or 0.8%~100% <20kHz
• Adjustable 200kHz to 1.4MHz switching frequency
• Dynamic headroom control
• Fault protections with latched flag indication
- String open/short circuit
- OVP
- OTP
- Optional output short-circuit fault protection switch
• Current matching ±0.7%
• 20 Ld 3x4 QFN package
Applications
• Notebook displays LED backlighting
• LCD monitor LED backlighting
• Multi-function printer scanning light source
V_IN = 4.5V~26.5V
Q1 OPTIONAL
V_OUT = 45V*, 6 x 50mA
ISL97672B
1 FAULT
2 VIN
4 VDC
LX 20
OVP 16
6 /FLAG
18 COMP
3 EN
5 PWM
17 RSET
8 FSW
9 AGND
PGND ₁₉
CH0 10
CH1 11
CH2 ₁₂
CH3 ₁₃
CH4 14
CH5 15
* V_IN > 12V
FIGURE 1. TYPICAL APPLICATION DIAGRAM
1.2
1.0
0.8
0.6
0.4
0.2
I_LED = 20mA
F_PWM = 20kHz
0.0
0 0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 3.6 4.0 4.4 4.8 5.2
PWM DIMMING DUTY CYCLE (%)
FIGURE 2. DIMMING LINEARITY AT 20kHz
November 22, 2013
1
FN7995.1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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