The R1201 Series are CMOS-based PWM step-up DC/DC converters, which are optimized to drive white LEDs with constant current. R1201 includes a 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 efficiency. 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.
|Input Voltage Range (Maximum Rating)||1.8 V to 5.5 V (6.5 V) (R1201xxx1A/3A)
1.8 V to 4.5 V (6.5 V) (R1201xxx2A/4A)
|Supply Current||Typ. 450 µA (R1201xxx3A/4A)
Typ. 500 µA (R1201xxx1A/2A)
|Standby Current||Typ. 1 µA|
|Feedback Voltage||0.2 V|
|Feedback Voltage Accuracy||±10 mV|
|Temperature-Drift Coefficient of Feedback Voltage||±150 ppm/°C|
|Oscillator Frequency||Typ. 1 MHz, Typ. 1.2 MHz|
|Maximum Duty Cycle||Typ. 91%|
|Switch ON Resistance||Typ. 1.35 Ω|
|UVLO Detector Threshold||Typ. 1.6 V|
|Lx Current Limit Protection||Typ. 700 mA|
|OVP Detector Threshold||Select from 9.5V, 14.0V, 18.5V, 20.6V, 21.6V|
|LED dimming control||by external PWM signal (Frequency 200Hz to 300kHz)|
|Ceramic capacitors are recommended||0.22 µF (R1201x02xA/ 03xA/ 04xA)
1 µF (R1201x05xA)
R1201N041A Efficiency vs. Output Current
The OVP threshold voltage, and the package for the ICs can be selected at the user's request.
|Product Name||Package||Quantity per Reel|
* As for R1201x052A/ 054A version, input voltage range is 1.8V to 4.5V.