LED driver provides 20% lower dropout voltage, extending battery life for low cost mobile products

As LED manufacturers improve their technology and reduce the voltage drop of their LEDs, in some applications a boost converter is no longer necessary. By driving LEDs directly from the battery using a low dropout current sink, the AHK3292 offers designers of entry-level phones and other mobile products a lighting solution that improves power efficiency and extends battery life while reducing cost.



Operating directly off a 2.7V to 5.5V input supply, the AHK3292 drives up to two LEDs. The 1X driver IC is ideal for driving LEDs with a low forward voltage drop. Low resistance, low dropout voltage current sinks allow the LEDs to operate close to the input supply voltage eliminating the need for an additional boost converter and extending battery life.

Maximum LED current is set by an external resistor (Rset) that enables designers to optimise linearity and provide smoother control. Fullscale LED current can be set to an upper limit of 30.2mA.



The output current for each LED is enabled, disabled and controlled by AnalogicTech’s Simple Serial Control (S2Cwire) interface. By replacing PWM control circuitry, this 32-step single-wire bus reduces the overhead on the system microcontroller, minimises LED flicker through constant-current digital control, and reduces noise.



LED output current accuracy is +/-10%. LED output current matching is +/-3%. The AHK3292 also features a low current shutdown mode.



Qualified over a -40 to +85 degrees C temperature range, the AHK3292 is available in a Pb-free 6-pin SOT23 package.