RICOH Manuals

The R1213K Series are low supply current, CMOS-based PWM step-up DC/DC converters. R1213K includes a soft start circuit, an under-voltage lockout circuit (UVLO), a thermal shutdown circuit, and a latch protection circuit. By simply using an inductor, resisters and capacitors as external components, a high-efficiency step-up DC/DC converter can be easily configured. The soft start time as well as phase compensation can be set with external resistors and capacitors. Built-in a timer latch protection circuit. Built-in a shutdown control circuit. It turns off the external Pch MOSFET at the latch protection time, so it cut off the power line from VDD to VOUT. To release the latch protection, change to the stand-by mode by the CE pin, or change the VDD voltage lower than the UVLO detect voltage.

The R1210Nxx2C/xx2D Series are CMOS-based PWM step-up DC/DC Converter controllers, with high accuracy, low supply current.

The R1210Nxx1x Series are CMOS-based PWM step-up DC/DC Converter, with high accuracy, low supply current.

The R1210N Series are low supply current, CMOS-based PWM step-up DC/DC converters. By simply using an inductor, a diode, and a capacitor as external components, a high-efficiency step-up DC/DC converter can be easily configured. The xx1 version with an internal output transistor and the xx2 version with an external transistor are available. The oscillator frequency can be selected from 100kHz or 180kHz. The xx1A version is also available, which contains a basic frequency changeover circuit that switches the oscillator frequency from 100kHz to 35kHz when output load is reduced. R1210N also has a function that detects drastic changes in output voltage and reduces the amount of overshoot/undershoot by switching control mode.

The RN5RK series is a CMOS-based VFM (Chopper) Step-up DC/DC converter IC with ultra low supply current and high output voltage accuracy.

The RN5RK Series are low supply current, CMOS-based VFM step-up DC/DC converters. By simply using an inductor, a diode, and a capacitor as external components, a high-efficiency step-up DC/DC converter can be easily configured. RN5RK comes in two versions: xx1 version with an internal output transistor and xx2 version with an external transistor.

The R1201x Series is a PWM control type step-up DC/DC converter IC with low supply current. It can drive white LEDs in constant current with high efficiency by using an inductor, a resistor and capacitors as external components.

The R1201N Series are CMOS-based PWM step-up DC/DC converters, which are optimized to drive white LEDs with constant current. R1201N includes a forward diode, an under-voltage lockout circuit (UVLO), and over-voltage protection circuit (OVP). By simply using an inductor, a resistor, and capacitors as external components, white LEDs can be driven with constant current and high efficiently. A diode is built-in; therefore it is possible to drive up to 5 serial LEDs without an external diode. The oscillator frequency can be selected from 1MHz or 1.2MHz. The LED current can be determined by the value of current setting resistor. The brightness of the LEDs can be adjusted quickly by applying a PWM signal (200Hz to 300kHz) to the CE pin.

R1203x series step-up DC/DC converter is dedicated for driving white LEDs with constant current. It is characterized by low supply current, high efficiency, high reliability and good EMI performance.

The R1203x Series are CMOS-based PWM step-up DC/DC converters, which are optimized to drive white LEDs with constant current

The R1218x Series are PWM control type step-up DC/DC converter ICs with low supply current.

The R1218x Series are CMOS-based PWM step-up DC/DC converters, which are optimized to drive white LEDs with constant current. R1218x includes an under-voltage lockout circuit (UVLO), over-voltage protection circuit (OVP). By simply using an inductor, (a diode), a resistor, and a capacitor as external components, white LEDs can be driven with constant current efficiently. R1218xxx1A for 2 to 4 lights contains an internal diode while R1218xxx2A for 5 to 7 lights requires an external diode. The LED current can be determined by the value of current setting resistor. The brightness of the LEDs can be adjusted by applying a PWM signal to the CE or VFB pin.

The R1205x Series are CMOS-based PWM control type step-up DC/DC converter ICs with low supply current. Each of these ICs consists of an NMOS FET, a diode, an oscillator, a PWM comparator, a voltage reference unit, an error amplifier, a current limit circuit, an under voltage lockout circuit (UVLO), an over-voltage protection circuit (OVP), a soft-start circuit, a Maxduty limit circuit, and a thermal shutdown protection circuit. This step-up DC/DC converter can be easily built with a few external components such as a coil, a resistor, and a capacitor. As the protection functions, the R1205x Series have a Lx peak current limit function, an over voltage protection (OVP) function, an under voltage lock out (UVLO) function and a thermal shutdown function. The R1205x Series present the R1205x8xxA version that is optimized for the constant voltage power source, and the R1205x8xxB version that is optimized for driving the white LED with the constant current. The R1205x8xxB is an adjustable version that can change the LED brightness dynamically by using a 200Hz to 300kHz PWM signal toward the CE pin. The R1205x Series are available in DFN1616-6B and TSOT-23-6 packages.

The R1205x series PWM step-up DC/DC converters are optimized for driving white LEDs with constant current and for general use.

The R1204x Series is a low-supply-current CMOS-based PWM step-up DC/DC converter. Internally, a single IC consists of an NMOS FET, an oscillator, a PWM comparator, a voltage reference unit, an error amplifier, a current limit circuit, an under voltage lockout circuit (UVLO), an over-voltage protection circuit (OVP), a soft-start circuit, a maximum duty cycle limit circuit, and a thermal shutdown protection circuit. By simply using an inductor, a resistor, capacitors and a diode as external components, a high-efficiency step-up DC/DC converter can be easily configured. As protection functions, the IC contains a thermal shutdown protection circuit, a current limit circuit, an OVP circuit, and an UVLO circuit. A thermal shutdown circuit detects overheating of the ICs and stops the operation to protect it from damage. A current limit circuit limits the peak current of Lx, and an OVP circuit detects the over voltage of output, and an UVLO circuit detects the low input voltage. The R1204x Series provide the R1204xxxA/D versions, which are optimized for serial driving of white LEDs with constant current, and the R1204xxxB/C/E/F versions, which are optimized for constant voltage driving. Among the R1204xxxB/C/E/F versions, only the R1204xxxC/F versions are equipped with PWM/VFM auto switching controls. The LED current can be determined by the value of current setting resistor. The brightness of the LED can be adjusted by changing the value of the current setting resistor.