LM2794中文资料具有模拟和 PWM 亮度控制功能的电流调节开关电容器 LED 电源数据手册TI规格书

描述 Description

The LM2794/95 is a fractional CMOS charge-pump that provides four regulated current sources. It accepts an input voltage range from 2.7V to 5.5V and maintains a constant current determined by an external sense resistor. The LM2794/5 delivers up to 80mA of load current to accommodate four White LEDs. The switching frequency is 325kHz. (min.) to keep the conducted noise spectrum away from sensitive frequencies within portable RF devices. Brightness can be controlled by both linear and PWM techniques. A voltage between 0V and 3.0V may be applied to the BRGT pin to linearly vary the LED current. Alternatively, a PWM signal can be applied to the SD pin to vary the perceived brightness of the LED. The SD pin reduces the operating current to 2.3µA (typ.) The LM2794 is shut down when the SD pin is low, and the LM2795 is shut down when the SD pin is high. The LM2794/95 is available in a DSBGA CSP package.

特性 Features

• Regulated Current Sources with ±0.5% Matching between any Two Outputs
• High Efficiency 3/2 Boost Function
• Drives One, Two, Three or four White LEDs
• 2.7V to 5.5V Input Voltage
• Up to 80mA Output Current
• Analog Brightness Control
• Active-Low or High Shutdown Input ('94/95)
• Very Small Solution Size and no Inductor
• 2.3µA (typ.) Shutdown Current
• 325kHz Switching Frequency (min.)
• Constant Frequency Generates Predictable Noise Spectrum
• Thin DSBGA Package: 2.08mm X 2.403mm X 0.600mm High