By using external capacitors, SII's charge pump ICs provide various power supply voltages such as constant currents and step-up voltages. This reduces the size of the board compared to when using coil-based DC-DC converters. The S-8813 Series has a constant current output and can drive up to three white LEDs. The S-8821 Series is a double step-up type IC with a PFM-type constant output. The S-882Z Series is a charge pump IC for step-up DC-DC converters and operates on a low voltage of 0.3 V.
The S-8813 Series, developed using CMOS technology, is a PFM control charge pump DC-DC converter with a built-in constant current circuit. Due to its constant output, this IC is ideal for the power supplies of current-driven LEDs.
The S-8813 Series has three outputs and can therefore drive three LEDs. When setting the output current value, the user can choose from a variable voltage type or a variable current setting resistance type.
This series also promotes system streamlining because a small ceramic capacitor can be used as the external capacitor (pump/input/output capacitor).
The S-8821 Series, developed using CMOS technology, is a step-up charge pump DC-DC converter IC with a regulation function.
The S-8821 Series consists of an oscillator, a controller, a reference voltage circuit, an error amplifier, and output switching transistors, and regulates the output voltage by using PFM control.
This series also promotes system streamlining because a small ceramic capacitor can be used as the external capacitor (pump/input/output capacitor).
The S-882Z Series is a step-up charge pump IC for converter startup and operates on a low voltage. Unlike conventional charge pump ICs, the S-882Z Series is developed completely using SOI (Silicon on Insulator) technology. This IC steps up a low input voltage of 0.3 to 0.35 V, enabling effective use of a very small power source. The stepped up power is stored in the external startup capacitor, and is discharged as the startup power for a step-up DC-DC converter once it reaches the discharge start voltage level.
This IC also has a power-off function that operates to autonomously stop IC operation when the output voltage from the connected step-up DC-DC converter reaches a certain value. This significantly reduces current consumption and extends the battery life.
Using this IC with a small SOT-23-5 package also enables high-density mounting.