R1203x series step-up DC/DC converter is dedicated for driving white LEDs with constant current. It is characterized by low supply current, high efficiency, high reliability and good EMI performance.
The R1203x Series are PWM control type step-up DC/DC converter ICs with low supply current, fully dedicated to driving white LEDs with constant current. Each IC consists of an NMOS FET, an oscillator, a PWM comparator, a voltage reference unit, an error amplifier, a current limit circuit, an under voltage lockout circuit (UVLO), and an over-voltage protection circuit (OVP). The LEDs current can be set by an external resistance value, and dimming can be adjusted via the CE pin according to a PWM signal.
| Input Voltage Range | 1.8V to 5.5V |
|---|---|
| Feedback Voltage | 0.2V |
| Feedback Voltage Accuracy | 1.0% |
| Maximum Duty Cycle | Typ. 91% |
| Switch ON Resistance | Typ. 1.35 Ohm |
| UVLO Detector Threshold | Typ. 1.6V |
| OVP Detector Threshold | Typ. 29.5V |
| Switching Control | PWM |
| LED dimming control | by external PWM signal (Frequency 200Hz to 300kHz) |
| Packages | DFN1616-6B, SOT-23-6 |
| Operating Temperature Range | -40 to 85 °C |
The feedback voltage is 0.2V, which results in small power loss by the current setting resistance.
The maximum duty cycle is internally fixed at a typical value of 91%.
The recommended inductance value is 10uH to 22uH.
The PWM signal frequency for dimming control should be between 200Hz and 300kHz.