Step-Up DC-DC Converter for RICOH R1205x SERIES User's Guide Technical Document
Summary
This advanced step-up DC/DC converter IC delivers stable power management optimized for portable electronic devices. Featuring integral protections such as UVLO, OVP, and thermal shutdown, the R1205x series can drive both constant voltage sources and adjustable white LEDs. The comprehensive manual guides designers through technical specifications, various application modes (including OLED supply), selecting optimal package options, and integrating reliable power solutions into their compact equipment designs.
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R1205x SERIES
STEP-UP DC/DC CONVERTER
NO.EA-272-120508
OUTLINE 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 R1205x8xx A version that is optimized for the constant voltage power source, and the R1205x8xx B version that is optimized for driving the white LED with the constant current. The R1205x8xx B is an adjustable version that can change the LED brightness dynamically by using a 200Hz to 300k Hz PWM signal toward the CE pin. The R1205x Series are available in DFN1616-6B and TSOT-23-6 packages.
FEATURES • Input Voltage Range ..................................................2.3V to 5.5V (R1205x8xx A) 1.8V to 5.5V (R1205x8xx B) • Supply Current ...........................................................Typ. 800μA • Standby Current .........................................................Max. 5μA • Feedback Voltage ......................................................1.0V±1.5% (R1205x8xx A)
0.2V±10m V (R1205x8xx B)
• Oscillator Frequency ..................................................Typ. 1.2MHz • Maximum Duty Cycle .................................................Typ. 91% • UVLO Function ························································ Typ.2.0V (Hys.Typ.0.2V) (R1205x8xx A)
Typ.1.6V (Hys.Typ.0.1V) (R1205x8xx B)
• Lx Current Limit Function...........................................Select from 350m A, 700m A • Over Voltage Protection .............................................Typ. 25V • LED dimming control (R1205x8xx B) ........................by external PWM signal (Frequency 200Hz to 300k Hz) • Thermal Protection Function......................................Typ.150ºC(Hys.Typ.50ºC) • Switch ON Resistance ...............................................Typ. 1.35Ω • Packages ...................................................................DFN1616-6B, TSOT-23-6 • Ceramic capacitors are recommended
APPLICATION • Constant Voltage Power Source for portable equipment • OLED power supply for portable equipment • White LED Backlight for portable equipment
Page Summary Contents For Step-Up DC-DC Converter for RICOH R1205x SERIES User's Guide Technical Document
Manual Details
| Brand | Ricoh |
|---|---|
| Pages | 21 |
| File Size | 486.35 KB |
| Published | June 04, 2026 |
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Frequently Asked Questions
Which R1205x version should I use for a constant current white LED application?
Use the R1205x8xxB version, which is optimized for driving white LEDs with constant current.
How do I dim the brightness of the LED using this converter?
For the R1205x8xxB, you can adjust brightness dynamically using an external PWM signal between 200Hz and 300kHz applied to the CE pin.
What safety protections are included in the R1205x Series?
It includes Lx peak current limit, Over Voltage Protection (OVP), Under Voltage Lockout (UVLO), and a thermal shutdown function.
What external components are needed to build this step-up DC/DC converter?
The converter can be easily built using basic external components such as a coil, a resistor, and a capacitor.