ST STP24DP05 LED恒流驱动方案
ST公司的STP24DP05是带输出误差检测的24位移位寄存器恒流LED驱动器,包含有8x3位串进并出的移位寄存器,输出级有24个可调整的电流源,提供5-80mA恒定电流来驱动LED.电源电压可低到3V,输出电压可高达20V,主要应用在LCD屏显示器.本文介绍了STP24DP05的主要特性, 方框图和典型应用电路图.STP24DP05 24-bit constant current LED sink driver with output error detection
The STP24DP05 is a monolithic, low voltage, low current power 24-bit shift register designed for LED panel displays. The device contains a 8 x 3-bit serial-in, parallel-out shift register that feeds a 8 x 3-bit D-type storage register. In the output stage, twenty-four regulated current sources were designed to provide 5-80 mA constant current to drive the LEDs.
The 8x3 shift registers data flow sequence order can be managed with two dedicated pins.The STP24DP05 has a dedicated pin to activate the outputs with a sequential delay, that will prevent inrush current during outputs turn-ON.
The device detection circuit checks 3 different conditions that can occur on the output line: short to GND, short to VO or open line.
The data detection results are loaded in the shift registers and shifted out via the serial line output. The detection functionality is activated with a dedicated pin or as alternative, through a logic sequence that allows the user to enter or exit from detection mode.
Through three external resistors, users can adjust the output current for each 8-channel group, controlling in this way the light intensity of LEDs. The STP24DP05 guarantees a 20 V output driving capability, allowing users to connect more LEDs in series.
The high clock frequency, 25 MHz, makes the device suitable for high data rate transmission.
The 3.3 V of voltage supply is useful for applications that interface any micro from 3.3 V.
主要特性:
■Low voltage power supply down to 3 V
■8 x 3 constant current output channels
■Adjustable output current through external resistors
■Short and open output error detection
■Serial data IN/Parallel data OUT
■Shift register data flow registers control
■Accepts 3.3 V and 5 V micro driver
■Output current: 5-80 mA
■25 MHz clock frequency
■High thermal efficiency package
图1.STP24DP05方框图
图2.STP24DP05典型应用电路图
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