基于LED1202 12路低静态电流LED驱动解决方案

ST公司的LED1202是12路低静态电流LED驱动器,保证了5V输出驱动功能,而每路能提供高达20 mA和电压裕度仅为350mV.每路的输出电流由8位模拟和12位数字调光控制来单独调整.慢开时间和慢关时间提高了系统的低噪音性能,而移相功能有助于降低浪涌电流,八种模式存储在内部寄存器而不需要MCU干预进行自动定序.器件的1.8V兼容的I²C接口基于快速模式指标,工作高达400kHz.工作电压2.6V-5V,每路的电流能力20mA,16mA时的12路的电流匹配度1%,2.5mA时的匹配度2%,8位模拟调光单独控制,12位本地PWM分辨率.LED1202具有LED开路检测和超温保护.主要用在RGB照明如可穿戴电子学,电池供电设备和手持附件.本文介绍了LED1202主要特性,框图和驱动器电路框图,以及评估板STEVAL-LLL007V1主要特性,电路图和材料清单.

The LED1202 is a 12-channel low quiescent current LED driver; it guarantees 5 V output driving capability and each channel is able to provide up to 20 mA with a headroom voltage of 350 mV (typ.) only. The output current can be adjusted separately for each channel by 8-bit analog and 12-bit digital dimming control.

A slow turn-on and turn-off time improves the system low noise generation performance; moreover, the phase shifting function helps to reduce the inrush current. Eight patterns can be stored in the internal registers for automatic sequencing without MCU intervention.
The pattern sequence can be also configured for duration time and number of repetition. For multi-device applications, a common clock domain can be shared for timing synchronization. The device includes thermal shutdown and open LED detection.

The device I²C interface is based on fast mode specification and works up to 400 kHz. Eight I²C addresses are possible by using two configuration pins (A0/A1) only.

The LED1202 is available in WLCSP20 package 1.71 x 2.16 x 0.5 mm with 0.4 mm pitch and in QFN20 3x3 package 3 x 3 x 0.6 mm with 0.5 mm pitch.

LED1202主要特性:

Supply range from 2.6 V to 5 V
12 channels for single LED
20 mA current capability per channel
1% (typ.) current matching at 16 mA and 2% (typ.) at 2.5 mA
1.8 V compatible I²C control interface
8-bit analog dimming individual control
12-bit local PWM resolution
8 programmable patterns
Programmable pattern sequence
Synchronization for multi-device application
Phase shifting between channels
Open LED detection
Overtemperature protection
8 configurable I²C slave addresses plus global address
Fault flag pin

LED1202应用:

• RGB LED lighting, fade-in and fade-out breathing effect,indicator lights for:
– Wearable electronics
– Battery powered devices
– Portable accessories

图1.LED1202简化框图

图2.LED1202驱动器电路框图

图3.菊花链共通时钟域配置概述图

评估板STEVAL-LLL007V1

Evaluation kit for the LED1202 12-channel low quiescent current LED driver STMicroelectronics STEVAL-LLL007V1 Evaluation Kit is configured to evaluate the operation of the LED1202 driver. The STEVAL-LLL007V1 Evaluation Kit includes the STEVAL-LLL007M1 main board and the STEVAL-LLL007D1 and STEVAL-LLL007D2 panel boards. The main board connects to a NUCLEO-L073RZ development platform running the STSW-LLL007FW firmware. This firmware comes with pre-configured random and wave patterns for use in standalone mode.

Users are able to develop your own pattern sequences by connecting the Nucleo platform to a PC running a dedicated GUI program, giving access to all the LED driver settings. The STEVAL-LLL007D1 panel board and the STEVAL-LLL007D2 panel board connected with an external power source via the J13 connector on the STEVAL-LLL007M1 board achieves maximum luminosity.

评估板STEVAL-LLL007V1主要特性:

3x LED1202 12-channel low quiescent current LED drivers embedded on main board
Can immediately drive 36 white LEDs available on main board, to help you get started
Includes additional panel boards to let you expand your development:
1 with 36 white LEDs
1 with 12 RGB LEDs
Designed for use with NUCLEO-L073RZ development platform running the STSW-LLL007FW firmware
E5V connector to supply STM32 Nucleo board and additional panels
Supplied with a range of default patterns
GUI for advanced driver configuration and customized pattern generation
CE Certified
RoHS and China RoHS compliant
WEEE compliant (2012/19/UE RAEE II)

评估板STEVAL-LLL007V1包括:

STEVAL-LLL007M1 main board
STEVAL-LLL007D1 panel board with 36 white LEDS
STEVAL-LLL007D2 panel board with 12 RGB LEDS
 

图4.评估板STEVAL-LLL007V1外形图

图5.评估板STEVAL-LLL007V1电路图(1)

图6.评估板STEVAL-LLL007V1电路图(2)

图7.评估板STEVAL-LLL007V1电路图(3)
评估板STEVAL-LLL007M1材料清单:

评估板STEVAL-LLL007D1材料清单:

评估板STEVAL-LLL007MD2材料清单: