RICOH R1203x Series PWM Step-up DC DC Converter for White LED User Guide & Data Sheet
Summary
The R1203x Series is a high-efficiency CMOS PWM step-up DC/DC converter engineered specifically for driving white LEDs with precise constant current control. Offering built-in protection features (UVLO/OVP) and brightness adjustment via programmable PWM signals, it ensures reliable and stable LED performance. This manual provides comprehensive technical specifications, detailed block diagrams, and typical application circuits, making it an essential resource for electronic designers creating portable lighting solutions, consumer electronics, and specialized equipment requiring superior white LED power management.
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R1203x Series
PWM Step-up DC/DC Converter for White LED
The R1203x Series are CMOS-based PWM step-up DC/DC converters, which are optimized to drive white LEDs with constant current. R1203x includes an under-voltage lockout circuit (UVLO), and over-voltage protection circuit (OVP). By simply using an inductor, a resistor, capacitors and a diode as external components, white LEDs can be driven with constant current and high efficiently. 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 300k Hz) to the CE pin.
FEATURES • Supply Current (IDD) ························Typ. 500μA (VIN=5.5, VFB=0V, Lx at no load) • Oscillator Frequency (fosc) ·············· 1.2MHz • Standby Current (Istandby) ·················Max. 5μA (VIN=5.5V,CE="L") • Oscillator Maximum Duty Cycle (Maxduty)··· Typ. 91% • Input Voltage Range (VIN) ···············1.8V to 5.5V • UVLO Detect Voltage (VUVLO) ········· Typ. 1.6V (Absolute maximum rating: 6.5V) • Coil-current Limit Circuit················· Current limit Typ. 700m A • Feedback Voltage (VFB)····················0.2V • Over Voltage Protection Circuit (OVP)···· 29.5V • Feedback Voltage Accuracy ···········± 10m V • Packages ······································· DFN1616-6B, SOT-23-6
BLOCK DIAGRAMS TYPICAL APPLICATION
VFB VIN LX VOUT
UVLO 0.22μF
Error Amp. VIN LX
PWM Comp. Ef fic ie nc
Switch CE VOUT
Control
OSC OVP
PWM Cntrl EN
GND VFB
Slope Current Current R1 Sense Shutdown 10Ω
Compensation Limit
delay
Chip Enable
CE GND
SELECTION GUIDES
Part No. .xxx : Specify the OVP Voltage.
Halogen Free Package Q'ty per Reel
DFN1616-6B 5,000 pcs R1203L.071B -TR SOT-23-6 3,000 pcs R1203N.071B -TR-FE
PACKAGES TYPICAL CHARACTERISTIC
DFN1616-6B SOT-23-6 7LEDs Efficiency vs. LED Current
Top View Bottom View 6 5 4 4 5 6
1 CE 1 CE
VIN=5.0V
2 VFB 2 VOUT
VIN=3.6V
3 Lx 3 VIN VIN=2.8V 4 GND 4 Lx 5 VIN 5 GND
Output Current IOUT (m A)
6 VOUT 6 VFB ∗) The tab is substrate level (GND).
APPLICATIONS • White LED driver for hand-held equipment
No.EK-271-111001 Step-up DC/DC Converter
Page Summary Contents For RICOH R1203x Series PWM Step-up DC DC Converter for White LED User Guide & Data Sheet
Manual Details
| Brand | Ricoh |
|---|---|
| Pages | 2 |
| File Size | 174.42 KB |
| Published | June 01, 2026 |
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Frequently Asked Questions
How can I adjust the LED brightness?
Apply a PWM signal (200Hz to 300kHz) to the CE pin.
What determines the constant current for the white LEDs?
The LED current is set by the value of the current setting resistor.
Is there protection against over and under voltage?
Yes, it includes an under-voltage lockout (UVLO) circuit and an over-voltage protection (OVP) circuit.
What is the input voltage range for the R1203x Series?
The input voltage range (VIN) is 1.8V to 5.5V.