PWM Low Supply Current Step-up DC/DC Converter
The R1208x is a low supply current CMOS-based PWM control step-up DC/DC converter. Internally, a single converter 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), an over-voltage protection circuit (OVP), a thermal shutdown protection circuit and current drivers for four white LED channels.
By simply using an inductor, a resistor, capacitors and a diode, 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 PWM signal (200 Hz to 300 kHz) to the CE pin.
Protection circuits included in the R1208x are a current limit circuit which limits the LX peak current, an UVLO circuit which prevents the malfunction of the device at low input voltage, an OVP circuit which monitors the excess output voltage and a thermal shutdown protection circuit which detects the overheating of the device and stops the operation to protect the device from damage.
The R1208x is offered in 12-pin DFN(PLP)2730-12 package.
|Input Voltage Range||2.7V to 22V|
|Supply Current||Typ. 600µA|
|Standby Current||Typ. 1.5µA|
|Lx Current Limit||Typ. 2A|
|Overvoltage Protection (OVP)||Typ. 23V / 33V / 43.5V|
|Oscillator Frequency||Typ. 750kHz / 450kHz|
|Maximum Duty Cycle||95% (750kHz) / 97% (450kHz)|
|Nch MOSFET ON Resistance||Typ. 0.28Ω|
|Undervoltage Lockout (UVLO)||Typ. 2.4V|
|Thermal Shutdown||Typ. 150°C|
|LED Dimming Control||By sending a PWM signal (200Hz to 300kHz) to the CE pin|
- ・LED backlight driver for LCD displays for portable equipment
- ・LED backlight driver for LCD displays for Tablets and Note PCs.
|Data Sheet||Flyer||Design Guide||Package Info.||Quality
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