Datasheet
Table Of Contents
- Features
- Typical Applications
- 1. Introduction
- 2. Ordering Information
- 3. Application Circuit
- 4. Absolute Maximum Ratings
- 5. Electrical Characteristics
- 6. Block Diagram
- 7. Pinout and Pin Description
- 8. Typical Application Circuit
- 9. Detailed Description
- 10. Fault Conditions
- 11. Applications Information
- 12. Control Registers
- 13. Detailed Register Descriptions
- 13.1 RAM (0x00 through 0x1F)
- 13.2 Main String Reference Voltage register (MREF, 0x20)
- 13.3 Color-Adjust String Reference Voltage register (CAREF, 0x21)
- 13.4 Fault Disable register (FAULT, 0x22)
- 13.5 Fault Status register (FAULTSTAT, 0x23), Read Only
- 13.6 Sleep register (SLEEP, 0x24)
- 13.7 Main String Duty Cycle register, High Byte (MDUTYHIGH, 0x34)
- 13.8 Main String Duty Cycle register, Low Byte (MDUTYLOW, 0x35)
- 13.9 Color Adjust String Duty Cycle register, High Byte (CADUTYHIGH, 0x36)
- 13.10 Color Adjust String Duty Cycle register, Low Byte (CADUTYLOW, 0x37)
- 13.11 Efficiency Optimizer Control Register (EOCTRL, 0x40)
- 13.12 Registers 0x60 and 0x61, EEPROM Access
- 14. I²C Serial Interface
- 15. Packaging Information
- 16. Datasheet Revision History
- Table of Contents

21
MSL2023/2024 [DATASHEET]
42063A–LED–02/2013
11.6 Selecting the Color-Adjust String Floating Buck Components
Figure 11-1. Floating buck LED driver.
The MSL2023/24 includes a driver for a constant off-time floating buck topology, shown in Figure 11-1, to convert the
main string voltage to a value appropriate for the color-adjust LED string. The buck is operated in continuous conduction
mode.
Continuous conduction operation is assured when the peak-to-peak ripple current in the inductor, ∆i
L
, is less than twice
the average LED current. A peak-to-peak ripple current magnitude of 15% of the average LED on-current is suggested,
i.e.
A
where I
AVE
is the average color-adjust LED string on-current. Choose I
AVE
appropriate for the color-adjust LEDs (Figure
11-1 on page 21 and Figure 11-2 on page 22) and calculate the peak string on-current using
A
DRV
CS
R
CS
COLOR LEDS
(COLOR-ADJUST STRING)
L
o
V
LED
D
1
TOFF
R
TOFF
C
o
C
i
Q
PGND
V
BUCK
+
-
WHITE LEDS
(MAIN STRING)
I
AVE
MSL2023/24
LED Driver
i
L
0.15I
AVE
=
I
PEAK
I
AVE
i
L
2
--------+=