R1214Z Series PWM/ VFM Step-up DC/DC Converter for White LED Applications NO.EA-327-170919 OUTLINE The R1214Z is a low supply current PWM/ VFM step-up DC/DC converter. Internally, the device consists of an Nch MOSFET driver, an oscillator, a PWM comparator, a voltage reference unit, an error amplifier, an overcurrent protection circuit, an under voltage lockout circuit (UVLO), an overvoltage protection circuit (L OVP, X LEDOVP), a thermal shutdown protection circuit and 2-channel current drivers for white LEDs. The R1214Z requires minimal external component count. By simply using an inductor, a resistor, capacitors and a diode, the white LEDs can be driven with constant current and high efficiency. 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 200 Hz to 300 kHz PWM signal to the PWM pin. The R1214Z provides the PWM control or the PWM/VFM auto switching control. The PWM control switches at fixed frequency rate in low output current in order to reduce noise. Likewise, the PWM/VFM auto switching control automatically switches from PWM mode to VFM mode in low output current in order to achieve high efficiency. RICOHs unique control method can suppress a ripple voltage in the VFM mode, thus the R1214Z can achieve both low ripple voltage at light load and high efficiency. The R1214Z provides an overcurrent protection circuit to limit the Lx peak current, an UVLO circuit to prevent the malfunction of the device at low input voltage, a L OVP circuit to monitor the excess L voltage, a LEDOVP X X circuit to monitor the excess LED1-2 voltage and a thermal shutdown protection circuit to detect the overheating of the device and stops the operation to protect the device from damage. The R1214Z is offered in a 9-pin WLCSP-9-P1 package. FEATURES Input Voltage Range (Maximum Rating) 2.7 V to 5.5 V (6.5 V) Supply Current Typ. 500 A Standby Current Typ. 0.2 A, Max. 5 A Overcurrent Protection Circuit Typ. 1.9 A Overvoltage Protection (OVP) Circuit Typ. 35 V LED1-2 Current Matching Circuit Max. 0.5% (R1214Zxx1C/ D, 20 mA) Max. 1.0% (R1214Zxx1A/ B, 20 mA) Oscillator Frequency Typ. 750 kHz/ 450 kHz Maximum Duty Cycle Typ. 96% (R1214Zx11x) Typ. 94% (R1214Zx21x) Nch ON Resistance Typ. 0.25 (V = 3.6 V) IN Undervoltage Lockout (UVLO) Circuit Typ. 2.4 V Thermal Shutdown Circuit Typ. 150C LED Dimming Control By sending a 200 Hz to 300 kHz PWM signal to the PWM pin Package WLCSP-9-P1 1 R1214Z NO.EA-327-170919 APPLICATION White LED backlight driver for LCD displays for portable equipment White LED backlight driver for LCD displays for Smartphones, Tablets and Note PCs SELECTION GUIDE The combinations of oscillator frequency, LED voltage and power controlling method are user-selectable options. Selection Guide Product Name Package Quantity per Reel Pb Free Halogen Free R1214Z2(y)1(z)-E2-F WLCSP-9-P1 5,000 pcs Yes Yes (y): Oscillator (z): LED Voltage 2(y)1(z) (z): Power Controlling Method Frequency (ILED = 20 mA) 211A 450 kHz 320 mV PWM/ VFM Auto Switching 221A 750 kHz 211B 450 kHz 320 mV PWM 211C 450 kHz 600 mV PWM/ VFM Auto Switching 221C 750 kHz 211D 450 kHz 600 mV PWM 2