The R1218x Series are CMOS-based PWM step-up DC/DC converters, which are optimized to drive white LEDs with constant current. R1218x includes an under-voltage lockout circuit (UVLO), over-voltage protection circuit (OVP). By simply using an inductor, (a diode), a resistor, and a capacitor as external components, white LEDs can be driven with constant current efficiently. R1218xxx1A for 2 to 4 lights contains an internal diode while R1218xxx2A for 5 to 7 lights requires an external diode. The LED current can be determined by the value of current setting resistor. The brightness of the LEDs can be adjusted by applying a PWM signal to the CE or VFB pin.
The R1218x Series are CMOS-based PWM step-up DC/DC converters designed to drive white LEDs with constant current. The series includes built-in under-voltage lockout (UVLO) and over-voltage protection (OVP) circuits. Efficiency is achieved using minimal external components: an inductor, a diode (internal or external depending on the specific part), a resistor, and a capacitor.
| Supply Current (Ipp) | Typ. 500nA |
|---|---|
| Oscillator Frequency (osc) | 1.2MHz |
| Standby Current (Istandby) | Max. 3nA |
| Oscillator Maximum Duty Cycle | Typ. 91% to 92% |
| Input Voltage Range (Vin) | 0.8V to 5.5V |
| Absolute Maximum Rating (Vin) | 6.5V |
| Feedback Voltage Accuracy | 10mV |
| Temp. coeff. of Feedback Voltage | + 150ppm/°C |
The oscillator frequency is typically 1.2MHz.
Yes, the series includes an under-voltage lockout circuit (UVLO) and an over-voltage protection circuit (OVP).
The available packages are DFN(PLP)1820-6 and SOT-23-6.