STEP-UP DC/DC CONVERTER with SHUTDOWN FUNCTION
The R1202x Series are CMOS-based PWM step-up DC/DC converter ICs with low supply current.
Each of these ICs consists of an NMOS FET, NPN transistor, 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 soft-start circuit, a Maxduty limit circuit, and a thermal shutdown protection circuit. By simply using an inductor, a resistor, and capacitors as external components, a high-efficiency step-up DC/DC converter can be easily configured. At the standby mode, a rectifier transistor can separate the output from the input.
The R1202x Series include a thermal shut-down circuit and an under-voltage lockout circuit (UVLO) which separate the output from the input to shut down the current when the over heat caused when the output is connected to the Gnd is detected and also during the UVLO detection. As other protection functions, the R1202x Series contain a cycle by cycle current limit circuit that limits the Lx peak current, and an over-voltage protection circuit (OVP) that detects the output overvoltage.
The R1202x Series offer three versions: the R1202xxxxA/B versions, which are optimized for constant-voltage power supply and the R1202xxxxD version, which is optimized to drive serial white LEDs with constant current.
While the R1202xxxxA version discharges the VOUT output to 0V at the shutdown, the R1202xxxxB version doesn't.
The brightness of the white LEDs can be adjusted quickly by applying a PWM signal (200Hz to 300kHz) to the CE pin.
The R1202x Series are available in DFN1616-6B and TSOT-23-6 packages.
|Input Voltage Range||2.3V to 5.5V (R1202xxxxA/B)
1.8V to 5.5V (R1202xxxxD)
|Supply Current||Typ. 800µA|
|Standby Current||Max. 5µA|
|Feedback Voltage||1.0V±15mV (R1202xxxxA/B)
|Oscillator Frequency||Typ. 1.2MHz|
|Maximum Duty Cycle||Typ. 91%|
|UVLO Function||Typ.2.0V (Hys.Typ.0.2V) (R1202xxxxA/B)
Typ.1.6V (Hys.Typ.0.1V) (R1202xxxxD)
|Lx Current Limit Function||Select from 350mA, 700mA|
|Over Voltage Protection||Select from 14V-23V (Refer the Selection Guide)|
|LED dimming control for R1202xxxxD||by external PWM signal (Frequency 200Hz to 300kHz)|
|Thermal Protection Function||Typ.150ºC(Hys.Typ.50ºC)|
|Built-in Auto Discharge Function||R1202xxxxA|
|NMOS ON Resistance||1.35Ω|
- ・Constant Voltage Power Source for portable equipment
- ・OLED power supply for portable equipment
- ・White LED Backlight for portable equipment
|Data Sheet||Flyer||Design Guide|
|Package Info.||Mark Info.||Quality Assurance Data|
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