User's Guide and Manual for RICOH R1204x Series

R1204x Series

PWM/VFM Step-up DC/DC Converter for White LED / PMOLED and General Use

The R1204x Series are CMOS-based PWM/VFM step-up DC/DC converters, which are optimized to drive white LEDs and OLED with constant current. There are two types. The A/D versions are optimized for the general use or the drive of PMOLED, and the B/C/E/F version is optimized for the serial drive of white LED with constant current. The R1204x includes an under-voltage lockout circuit (UVLO), a soft-start circuit, and an over-voltage protection circuit (OVP), a thermal shutdown circuit. By simply using an inductor, divider resisters, and capacitors as external components, OLED and white LEDs can be driven with high efficiently. The A/D version can set white LED current with feedback resister (R1). The brightness of the LEDs and the soft-start time can be adjusted by applying a PWM signal (200Hz to 300k Hz) to the CE pin. In addition to DFN(PLP)1820-6, 0.95mm thickness TSOT-23-6 is available.

FEATURES • Supply Current (IDD) ························Typ. 800μA (VIN= 5.5V, VFB = 0V, Lx at no load) • UVLO Detect Voltage (VUVLO)·······Typ. 2.0V • Standby Current (Istandby)··················Max. 5μA (VIN= 5.5V, VCE = 0V) • Coil-current Limit Circuit ··············Current Limit Typ. 900m A • Input Voltage Range (VIN) ···············2.3V to 5.5V • Over Voltage Protection Circuit (OVP) ···Typ. 23V, Typ. 33V, Typ. 42V • Feedback Voltage (VFB) ·················0.2V (A/D Version) • Soft Start Time (tstart)·····················Controllable by PWM signal

1.0V (B/C/E/F Version) to the CE pin (A/D Version)

• Feedback Voltage Accuracy ···········± 10m V (A/D Version) Typ. 10ms (B/C/E/F Version)

± 15m V (B/C/E/F Version) • Thermal Shutdown Circuit ···········Stops at 150°C

• Oscillator Frequency (fosc)···············1MHz (A/B/C Version), 750k Hz (D/E/F Version) • Packages ·····································DFN(PLP)1820-6, TSOT-23-6 • Oscillator Maximum Duty Cycle (Maxduty)···Typ. 91% (A/B/C Version), Typ. 92% (D/E/F Version)

BLOCK DIAGRAMS R1204xx1x A/D R1204xx1x B/C/E/F

ff ic ie cy

(PWM, VFB=0.2V) (B/E:PWM, C/F:PWM/VFM auto switching, VFB=1.0V)

VFB VIN LX VOUT

VFB VIN LX VOUT

Err. Amp. UVLO

PWM Comp. Err. Amp. UVLO

PWM Comp. VFM Control

Driver

Control S Driver

vref Control S

Oscillator OVP

PWM Oscillator OVPSoft-start

Control Current

Slope Com- Current

EN Limit Thermal Slope Com- Current Current Thermal

pensation sense

Shutdow pensation Limit sense Shutdow

Soft-start

Shutdow delay

CE CE

GNDCE GNDCE

ff ic ie nc

Blue Line : only R1204xx1x C/F

SELECTION GUIDES TYPICAL APPLICATIONS

Halogen Free Package Q'ty per Reel Part No. R1204xx1x A/D R1204xx1x B/C/E/F

DFN(PLP)1820-6 5,000 pcs R1204K .x.12.∗ -TR VIN = 2.3V to 5.5V VIN = 2.3V to 5.5V

TSOT-23-6 3,000 pcs R1204N .x.13.∗ -TR-FE

.x. : Specify the OVP voltage.

(1) OVP : 23V, (2) OVP : 33V, (3) OVP : 42V VIN LX

VIN LX

VLED =

.∗ : Specify the control, feedback voltage and oscillator frequency.

VIN -VFB to

VFB=0.2V VFB=1.0V CE VOUT CE VOUT

VOVP1MIN-3V

（A）PWM, 1MHz （B）PWM, 1MHz R2

（D）PWM, 750k Hz （C）PWM/VFM auto switching, 1MHz GND VFB

GND VFB

（E）PWM, 750k Hz R1

（F）PWM/VFM auto switching, 750k Hz

L1: 10μH(A) or 22μH(D)

L1: 10μH(B/C) or 22μH(E/F),

PACKAGES (Top View) TYPICAL CHARACTERISTIC DFN(PLP)1820-6 TSOT-23-6 Efficiency vs. LED Output Current L=22μH (VLF302512MT220) 6 5 4 6 5 4

R1204xx1x D（10 LEDs） R1204xx1x F（VOUT=31V）

Vin= 3.2 V Vin= 3.6 V Vin= 3.2 V

Vin= 4.2 V Vin= 5 V Vin= 3.6 V Vin= 5 V

1 VOUT 4 VIN 1 LX 4 CE 2 LX 5 CE 2 GND 5 VOUT 3 GND 6 VFB 3 VFB 6 VIN Output Current [m A]

Output Current [m A]

∗) The tab is substrate level (GND).

APPLICATIONS • OLED power supply for hand-held equipment • White LED backlight for hand-held equipment

No.EK-284-120522 Step-up DC/DC Converter