NCP5009DMR2 ON Semiconductor, NCP5009DMR2 Datasheet - Page 10

• Manufacturer Part Number: NCP5009DMR2
• Description: IC LED DRVR WHT BCKLT 10MICROSMD
• Manufacturer: ON Semiconductor
• Type: Backlight, White LEDr

Specifications of NCP5009DMR2

• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 1
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: White LED
• Frequency: 5MHz
• Voltage - Supply: 2.7 V ~ 6 V
• Voltage - Output: 15V
• Mounting Type: Surface Mount
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• Operating Temperature: -25°C ~ 85°C
• Current - Output / Channel: 75mA
• Internal Switch(s): Yes
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Efficiency: -
• Other names: NCP5009DMR2OSTR

Set Up Output Current Range
from the current sunk to ground on I
multiplied by the programmed value (Bn) and then
multiplied by the constant factor ratio (k = 746) in the
current mirror.
Iout sense and the Iout reference internally fixed.
The output current reference is:
The current sunk to ground on PHOTO pin is subtracted
The constant factor k is a ratio between the current on
Ipeak = Ivalley + (I
GND
GND
R
30 k
Q1
NPN−PHOTO
ref
Photo
I
ref
1
1
ref
− Iphoto) * Bn * k.
GND
GND
V
V
bat
bat
−
−
+
+
V
V
bat
bat
ref
BandGap
BandGap
pin. The result is
Figure 20. Functional Diagram
NCP5008, NCP5009
Iphoto
1
GND
http://onsemi.com
1
1
GND
10
1
Where k = 746, Bn represents the bit of the internal shift
register, range from 1 to 7, and Ivalley = (I
* 0.5 * k.
We can write also Ipeak = (I
resistor (resistor on I
GND
I
ref
1
Please find below the formula to quickly calculate R1
GND
1
1:Bn
I = (I
V
bat
ref
ref
−Iphoto)*(Bn+0.5)
I ref + 1.24
pin):
GND
1:746
ref
2:1
R1
− Iphoto) * (Bn + 0.5) * k.
= (I
ref
−Iphoto)*746*(Bn+0.5)
Iout Reference
ref
− Iphoto)