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
24
MSL2023/2024 [DATASHEET]
42063A–LED–02/2013
11.7 PWM and LED Brightness
Figure 6-1 on page 12 is a block diagram that shows how the MSL2023 controls the brightness of the LEDs. The duty
cycle of each string equals the value programmed into the 12-bit PWM control registers MainDuty[11:0] and
ColorAdjustDuty[11:0], (registers 0x34 through 0x37). The frequency of the PWM dimming is 400Hz. The dimming
signals for the two strings are 180º out of phase.
Figure 6-2 on page 13 is a block diagram that shows how the MSL2024 controls the brightness of the LEDs. The duty
cycle of each string equals the duty cycle of the inputs at PWM1 (main string) and PWM2 (color-adjust string). The
frequency of each string’s PWM dimming signal equals the frequencies of the respective input signals. The frequency
range of the PWM1 input is 120Hz to 22kHz, while the minimum on-time for the main string driver output G is 2µs. The
frequency range of the PWM2 input is 200Hz to 500Hz.
12. Control Registers
Table 12-1. Register map
(1)
.
Notes: 1. Do not change the contents of undefined bits or unlisted registers.
Address and
Register name
Function
Default
value
(2)
Bit functions
D7 D6 D5 D4 D3 D2 D1 D0
Control and monitor registers
0x00 to 0x1F RAM 0xXX Free RAM
0x20 MREF
Main String
Feedback
Reference
Voltage
0x64 M
REF
= 2mV per LSB
0x21 CAREF
Color-Adjust
String Reference
Feedback Voltage
0x64 CA
REF
= 2mV per LSB
0x22
FAULT
DISABLE
Color-Adjust Fault
Disable
0x00
– – – – – TSDMASK OCDIS SCDIS
0x23 FAULTSTAT Fault Status
Read
Only
– – – – –TSDOCFLTSCFLT
0x24 SLEEP Configuration 0x00
– – – – – – – SLEEP
0x34 MDUTYHIGH
Main String Duty
Cycle High
Byte
0xFF MainDuty[11:4] MSL2023 ONLY
0x35 MDUTYLOW
Main String Duty
Cycle Low
Bits
0x0F
– – – – MainDuty[3:0] MSL2023 ONLY
0x36 CADUTYHIGH
Color Adjust
String Duty
Cycle High Byte
0xFF ColorAdjustDuty[11:4] MSL2023 ONLY
0x37 CADUTYLOW
Color Adjust
String Duty
Cycle Low Bits
0x0F
– – – – ColorAdjustDuty[3:0] MSL2023 ONLY
0x40 EOCTRL
Efficiency
Optimizer
0xE5
– – – – DThresh[3:0]
0x60 E2ADDR
EEPROM
Address
0x00
– EEPROM Address Pointer
0x61 E2CTRL EEPROM Control 0x00
– – – – – RWCTRL[2:0]