RICOH Manuals

The R1283K Series are dual output CMOS-based PWM step-up/inverting DC/DC converters. R1283K includes a soft start circuit, an under-voltage lockout circuit (UVLO), and a latch protection circuit. By simply using inductors, resistors, capacitors, and diodes as external components, a high-efficiency step-up/inverting DC/DC converter can be easily configured. While R1280D need using an external transistor, R1283K has internal 400mΩ ON resistance transistors for both step-up and inverting. Start-up sequence of two DC/DC converters can be selected. Since the shutdown sequence can also be set by the auto-discharge function of the inverting DC/DC converter, the products are ideally suitable for applications that require setting of power supply start-up/shutdown sequence for CCD, LCD, and OLED.

The R1286 series 2ch DC/DC power converter is designed for AMOLED display power source. It contains a step up DC/DC converter and an inverting DC/DC converter. Step up DC/DC converter generates boosted output voltage to 4.6V ~ 5.8V(Selectable). Inverting DC/DC converter generates negative voltage down to -2.0V ~ -6.0V(Selectable) that is dynamically adjustable with single wire interface signal. R1286 consist of a voltage reference, error amplifiers, an oscillator, PWM control circuits, over current protection circuits, short protection circuits, an under voltage lockout circuit (UVLO), thermal shutdown circuit, a NMOS driver and a synchronous PMOS switch for boost converter, a PMOS driver and a synchronous NMOS switch for inverting converter, and so on. High efficiency boost and inverting DC/DC converters can be composed with two external inductors and three capacitors.

The R1286K Series are CMOS-based PWM step-up/inverting DC/DC converters featuring 250mA×2 output current with synchronous rectifier. R1286K includes a soft start circuit, an under-voltage lockout circuit (UVLO), a latch protection circuit, a thermal shutdown circuit, and a shutdown circuit. By simply using two inductors and three capacitors as external components, a high-efficiency step-up/inverting DC/DC converter can be easily configured. R1286K is available in two types: R1286K001B is the type to which the output voltage (VOUTP and VOUTN) can be adjusted by external resistors. R1286KxxxA/C~M are the type to which the step-up output voltage (VOUTP) is internally fixed and the inverting output voltage (VOUTN) can be adjusted dynamically by the single wire interface. The R1286K has a sequenced start up. After the CE pin is enabled, the step-up output is starting up followed by the inverting output after a delay time. As for shutdown, both outputs will be turned off by the auto-discharge function. R1286K is used for applications such as LCD and AMOLED displays.

The R1215D Series are CMOS-based PWM step-up DC/DC converter controllers with low supply current. Each of the R1215D Series consists of an oscillator, a PWM comparator circuit, a reference voltage unit, an error amplifier, a reference current unit, a protection circuit, and an under voltage lockout (UVLO) circuit. A low ripple, high efficiency step-up DC/DC converter can be composed of this IC with some external components, or an inductor, a diode, a power MOSFET, resisters, and capacitors. Maximum duty cycle and the soft start time are easily adjustable with external resistors and capacitors. As for the protection circuit, after the soft-starting time, if the maximum duty cycle is continued for a certain period, the R1215D Series latch the external driver with its off state, or the latch-type protection circuit works. The delay time for latch the state can be set with an external capacitor. To release the protection circuit, restart with power-on (Voltage supplier is equal or less than UVLO detector threshold level).

The R1215D Series are low supply current CMOS PWM step-up DC/DC controllers. R1215D does not include an internal output transistor. By simply using a power MOS, an inductor, a diode, resistors, and capacitors as external components, a high-efficiency step-up DC/DC converter can be easily configured.

R1212D series step-up DC/DC controller is a low-power, low-noise step-up DC/DC converter controller, suitable for various products that require high reliability, high efficiency and small size.

R1211x Series PWM step-up DC/DC controller is a low supply current CMOS-based PWM step-up DC/DC converter controller.

RP401x Series are high efficiency, step-up DC/DC converter ICs packaged in compact 5pin SOT23-5， or 6pin DFN(PLP)1820-6. This IC can start up from low voltage (Typ.0.6V), therefore, it is suitable for using with single or 2 serial alkaline batteries, or a nickel-metal-hydride (NiMH) battery, or one-cell Lithium-ion (Li+) battery. This IC consists of an oscillator, a reference voltage unit with soft start, a chip enable circuit, an error amplifier, phase compensation circuits, a slope circuit, a PWM control circuit, a start-up circuit, a PWM/VFM mode control circuit, internal switches and a protection circuit. A low ripple high efficiency step-up DC/DC converter can be composed of the RP401x with only an inductor, a diode, (resisters for adjustable type), and capacitors. The output voltage of the RP401K001s is adjustable, and others are fixed internally. The output voltage range is from 1.8V to 5.5V. RP401Kxx1A/B series have a MODE pin to alternate between PWM fix and PWM/VFM automatic shift to improve the efficiency at light load. If MODE pin is set 'H', the mode is PWM fix, and when the MODE pin is set 'L', PWM/VFM automatic shift. The RP401xxx1C and D do not have MODE pin. The RP401xxx1C is PWM/PFM alternative type, and the RP401xxx1D is PWM fixed type.

The RP401x Series are CMOS-based PWM/VFM step-up DC/DC converters which can start-up from Typ. 0.6V.

RP400xxx1B Series high efficiency, small packages, step-up DC/DC converters

RP400xxx1A Series are high efficiency, step-up DC/DC converter ICs packaged in compact 5pin SOT23 or 6pin DFN(PLP). This converter starts up of low voltage (Typ.0.8V) operation from one to two alkaline or a nickel-metal-hydride (NiMH) or one-cell Lithium-ion (Li+) battery. This IC consists of a reference voltage unit with soft start, a chip enable circuit, an error amplifier, phase compensation circuits, a slope circuit, a PWM control circuit, a start-up circuit, a PWM/VFM mode control circuit, internal switches and a protection circuit. As a protection circuit, RP400xxx1A has a current limit circuit which limits the peak current of the inductor at each clock cycle. A low ripple high efficiency step up DC/DC converter can be composed of RP400xxx1A Series with only an inductor, a diode and capacitors. This converter is based on a fixed frequency current mode PWM control which goes to power save mode (VFM mode) at light load automatically. RP400xxx1A Series has built-in Anti-ringing switch to prevent switching node from ringing, when the converter enters the discontinuous current mode. The output voltage of RP400K001A can be set within 1.8~5.0V (recommended range of output voltage) by external divider resistors.

The RP400x series are CMOS-based automatic switch PWM- or VFM-controlled step-up DC/DC converters. RP400x includes a soft start circuit. By simply using an inductor, a capacitor, a diode, and (resistors) as external components, a high-efficiency step-up DC/DC converter can be easily configured. Due to current mode PWM control, the RP400x provides a fast response and high efficiency. Ceramic output capacitors can be used. The output voltage can be selected from the internally fixed or the externally adjustment. The RP400x has an anti-ringing switch that prevents inductor current from ringing in PWM discontinuous mode. RP400x switches automatically to VFM control in low output current, keeping high efficiency. In addition to SOT-23-5 package, a 1.8mm × 2.0mm square DFN(PLP)1820-6 package is also available.

R1213K Series are CMOS-based, PWM control low consumption current step-up DC/DC converter ICs.