R1218XXX1A RICOH [RICOH electronics devices division], R1218XXX1A Datasheet
R1218XXX1A
Related parts for R1218XXX1A
R1218XXX1A Summary of contents
Page 1
... The R1218X can drive white LEDs with high efficiency with low supply current. A diode is built-in the R1218XXX1A, therefore it is possible to drive up to 4LEDs without an external diode. The R1218XXX2A, an external diode is necessary, however serial LEDs can be driven with the R1218XXX2A ...
Page 2
... R1218X BLOCK DIAGRAMS R1218XXX1A Err. Amp PWM Comp + + – – ref ref ref ref Shu tdown delay R1218XXX2A Err. Amp PWM Comp + + – – Vref Vref Vref Vref Shutdown delay ...
Page 3
SELECTION GUIDE The OVP threshold voltage and the package for the ICs can be selected at the user's request. The selection can be available by designating the part number as shown below; R1218xxxxx- Code ...
Page 4
... Chip Enable Pin V Feedback Pin FB Lx Switching Pin (Open Drain Output) GND Ground Pin V Power Supply Input Pin IN V Output Voltage OUT Item R1218XXX1A R1218XXX2A R1218XXX1A R1218XXX2A R1218NXXXA suspended in air R1218KXXXA*Note1 Conditions V =5.5V, V =0V load =5.5V falling ...
Page 5
... GND GND GND GND Conditions V =3. =3.6V, -40 C Topt =5.5V, V = =3.6V, I =100mA IN SW R1218XXX1A V =20V LX R1218XXX2A V =29V LX V =3. =3.6V =0V IN OUT FB V =3.6V =0V IN OUT FB R1218X021A R1218X031A V =3.6V IN R1218X041A V rising OUT ...
Page 6
R1218X VFB Voltage, Oscillator Frequency, Maximum Duty Test Circuit GND GND GND GND TYPICAL APPLICATIONS ...
Page 7
PWM signal duty cycle can be used up to the maximum LED current and minimum LED current as in the next formulas. I =(0.2-R2*(VH-0.2)/(R3+R4))/R1 LEDMIN I =(0.2-R2*(VL-0.2)/(R3+R4))/R1 LEDMAX For example, supposed that the PWM signal level is ...
Page 8
R1218X TYPICAL CHARACTERISTICS 1) Efficiency vs 2LED) L:LQH32CN220 Topt=25 C LED R1218X021A 100 LED Current I R1218X021A 100 ...
Page 9
R1218X031A 100 LED 電流 I LED 3. Efficiency vs. ILED (4 LED ) L: LQH32CN220, Topt=25 C R1218X041A 100 ...
Page 10
R1218X 4. Efficiency vs. I (6LED) L: LQH32CN220, Diode: CRS02 LED R1218X062A 100 LED Current I R1218X062A 100 ...
Page 11
Output Voltage Waveform (Topt=25 C) R1218X021A 25 CE Input Voltage Output Voltage 0.8 1.6 2.4 Time (ms) 6. PWM Dimming Control (4 LED) 6-1. Duty vs. LED Current (Topt=25 C) R1218X041A 25 22.5 ...
Page 12
R1218X 7. PWM Dimming Control (6 LED) 7-1. Duty vs. LED Current (Topt=25 C) R1218X062A 25 22.5 20 17.5 15 12.5 10 7 DUTY (%) 7-2. Output Voltage Waveform (Topt=25 C) R1218X062A 50 CE ...
Page 13
Oscillator Frequency vs. Temperature R1218x041A 1400 1350 1300 1250 1200 1150 1100 1050 1000 -50 - Temperature Topt (°C) 12. OVP Detector Threshold/Released Voltage vs. Temperature R1218x041A 20.5 20 19.5 19 18.5 18 17.5 17 16.5 -50 ...
Page 14
R1218X 15. OVP Transient Response (Topt=25 C) R1218X021A 15 12.5 OVP Voltage 10 7 Time (ms) R1218X062A 35 OVP Voltage Time (ms) 16. Efficiency ...