HT7938数据手册Holtek中文资料规格书

描述 Description

 

HT7938 is high efficiency boost converter with constant current output to provide backlight in handheld devices. Series connection of LEDs provides constant identical LED currents resulting in uniform brightness. The continuous LED current is set with FB pin regulated voltage across an external sense resistor (RFB) connected from that pin to ground. The built-in open load protection prevents the damage resulting from an open circuit condition. Low 200mV feedback voltage minimizes power loss in the current setting resistor for better efficiency. HT7938 switches at rates up to 1.2MHz to allow the use of extremely small inductor and filter capacitor.

 

特性 Features

• Efficiency up to 85% at VIN=3.6V, 9LEDs, ILED=20mA
• 1.2MHz fixed switching frequency
• Low Standby Current: 0.1µA (typ.) at VEN= 0V 
• Matches LED current
• Tiny inductor and capacitors
• Up to 10 strings White-LED (LED VF(Max.)=3.5V)
• Tiny 6-lead SOT23-6 package
• Built in OVP, OCP, OTP, UVLO protection